1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the Expr constant evaluator.
10//
11// Constant expression evaluation produces four main results:
12//
13// * A success/failure flag indicating whether constant folding was successful.
14// This is the 'bool' return value used by most of the code in this file. A
15// 'false' return value indicates that constant folding has failed, and any
16// appropriate diagnostic has already been produced.
17//
18// * An evaluated result, valid only if constant folding has not failed.
19//
20// * A flag indicating if evaluation encountered (unevaluated) side-effects.
21// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1),
22// where it is possible to determine the evaluated result regardless.
23//
24// * A set of notes indicating why the evaluation was not a constant expression
25// (under the C++11 / C++1y rules only, at the moment), or, if folding failed
26// too, why the expression could not be folded.
27//
28// If we are checking for a potential constant expression, failure to constant
29// fold a potential constant sub-expression will be indicated by a 'false'
30// return value (the expression could not be folded) and no diagnostic (the
31// expression is not necessarily non-constant).
32//
33//===----------------------------------------------------------------------===//
34
35#include "Interp/Context.h"
36#include "Interp/Frame.h"
37#include "Interp/State.h"
38#include "clang/AST/APValue.h"
39#include "clang/AST/ASTContext.h"
40#include "clang/AST/ASTDiagnostic.h"
41#include "clang/AST/ASTLambda.h"
42#include "clang/AST/Attr.h"
43#include "clang/AST/CXXInheritance.h"
44#include "clang/AST/CharUnits.h"
45#include "clang/AST/CurrentSourceLocExprScope.h"
46#include "clang/AST/Expr.h"
47#include "clang/AST/OSLog.h"
48#include "clang/AST/OptionalDiagnostic.h"
49#include "clang/AST/RecordLayout.h"
50#include "clang/AST/StmtVisitor.h"
51#include "clang/AST/TypeLoc.h"
52#include "clang/Basic/Builtins.h"
53#include "clang/Basic/TargetInfo.h"
54#include "llvm/ADT/APFixedPoint.h"
55#include "llvm/ADT/Optional.h"
56#include "llvm/ADT/SmallBitVector.h"
57#include "llvm/Support/Debug.h"
58#include "llvm/Support/SaveAndRestore.h"
59#include "llvm/Support/raw_ostream.h"
60#include <cstring>
61#include <functional>
62
63#define DEBUG_TYPE "exprconstant"
64
65using namespace clang;
66using llvm::APFixedPoint;
67using llvm::APInt;
68using llvm::APSInt;
69using llvm::APFloat;
70using llvm::FixedPointSemantics;
71using llvm::Optional;
72
73namespace {
74 struct LValue;
75 class CallStackFrame;
76 class EvalInfo;
77
78 using SourceLocExprScopeGuard =
79 CurrentSourceLocExprScope::SourceLocExprScopeGuard;
80
81 static QualType getType(APValue::LValueBase B) {
82 return B.getType();
83 }
84
85 /// Get an LValue path entry, which is known to not be an array index, as a
86 /// field declaration.
87 static const FieldDecl *getAsField(APValue::LValuePathEntry E) {
88 return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer());
89 }
90 /// Get an LValue path entry, which is known to not be an array index, as a
91 /// base class declaration.
92 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) {
93 return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer());
94 }
95 /// Determine whether this LValue path entry for a base class names a virtual
96 /// base class.
97 static bool isVirtualBaseClass(APValue::LValuePathEntry E) {
98 return E.getAsBaseOrMember().getInt();
99 }
100
101 /// Given an expression, determine the type used to store the result of
102 /// evaluating that expression.
103 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) {
104 if (E->isRValue())
105 return E->getType();
106 return Ctx.getLValueReferenceType(E->getType());
107 }
108
109 /// Given a CallExpr, try to get the alloc_size attribute. May return null.
110 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) {
111 const FunctionDecl *Callee = CE->getDirectCallee();
112 return Callee ? Callee->getAttr<AllocSizeAttr>() : nullptr;
113 }
114
115 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr.
116 /// This will look through a single cast.
117 ///
118 /// Returns null if we couldn't unwrap a function with alloc_size.
119 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) {
120 if (!E->getType()->isPointerType())
121 return nullptr;
122
123 E = E->IgnoreParens();
124 // If we're doing a variable assignment from e.g. malloc(N), there will
125 // probably be a cast of some kind. In exotic cases, we might also see a
126 // top-level ExprWithCleanups. Ignore them either way.
127 if (const auto *FE = dyn_cast<FullExpr>(E))
128 E = FE->getSubExpr()->IgnoreParens();
129
130 if (const auto *Cast = dyn_cast<CastExpr>(E))
131 E = Cast->getSubExpr()->IgnoreParens();
132
133 if (const auto *CE = dyn_cast<CallExpr>(E))
134 return getAllocSizeAttr(CE) ? CE : nullptr;
135 return nullptr;
136 }
137
138 /// Determines whether or not the given Base contains a call to a function
139 /// with the alloc_size attribute.
140 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) {
141 const auto *E = Base.dyn_cast<const Expr *>();
142 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E);
143 }
144
145 /// Determines whether the given kind of constant expression is only ever
146 /// used for name mangling. If so, it's permitted to reference things that we
147 /// can't generate code for (in particular, dllimported functions).
148 static bool isForManglingOnly(ConstantExprKind Kind) {
149 switch (Kind) {
150 case ConstantExprKind::Normal:
151 case ConstantExprKind::ClassTemplateArgument:
152 case ConstantExprKind::ImmediateInvocation:
153 // Note that non-type template arguments of class type are emitted as
154 // template parameter objects.
155 return false;
156
157 case ConstantExprKind::NonClassTemplateArgument:
158 return true;
159 }
160 llvm_unreachable("unknown ConstantExprKind");
161 }
162
163 static bool isTemplateArgument(ConstantExprKind Kind) {
164 switch (Kind) {
165 case ConstantExprKind::Normal:
166 case ConstantExprKind::ImmediateInvocation:
167 return false;
168
169 case ConstantExprKind::ClassTemplateArgument:
170 case ConstantExprKind::NonClassTemplateArgument:
171 return true;
172 }
173 llvm_unreachable("unknown ConstantExprKind");
174 }
175
176 /// The bound to claim that an array of unknown bound has.
177 /// The value in MostDerivedArraySize is undefined in this case. So, set it
178 /// to an arbitrary value that's likely to loudly break things if it's used.
179 static const uint64_t AssumedSizeForUnsizedArray =
180 std::numeric_limits<uint64_t>::max() / 2;
181
182 /// Determines if an LValue with the given LValueBase will have an unsized
183 /// array in its designator.
184 /// Find the path length and type of the most-derived subobject in the given
185 /// path, and find the size of the containing array, if any.
186 static unsigned
187 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
188 ArrayRef<APValue::LValuePathEntry> Path,
189 uint64_t &ArraySize, QualType &Type, bool &IsArray,
190 bool &FirstEntryIsUnsizedArray) {
191 // This only accepts LValueBases from APValues, and APValues don't support
192 // arrays that lack size info.
193 assert(!isBaseAnAllocSizeCall(Base) &&
194 "Unsized arrays shouldn't appear here");
195 unsigned MostDerivedLength = 0;
196 Type = getType(Base);
197
198 for (unsigned I = 0, N = Path.size(); I != N; ++I) {
199 if (Type->isArrayType()) {
200 const ArrayType *AT = Ctx.getAsArrayType(Type);
201 Type = AT->getElementType();
202 MostDerivedLength = I + 1;
203 IsArray = true;
204
205 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
206 ArraySize = CAT->getSize().getZExtValue();
207 } else {
208 assert(I == 0 && "unexpected unsized array designator");
209 FirstEntryIsUnsizedArray = true;
210 ArraySize = AssumedSizeForUnsizedArray;
211 }
212 } else if (Type->isAnyComplexType()) {
213 const ComplexType *CT = Type->castAs<ComplexType>();
214 Type = CT->getElementType();
215 ArraySize = 2;
216 MostDerivedLength = I + 1;
217 IsArray = true;
218 } else if (const FieldDecl *FD = getAsField(Path[I])) {
219 Type = FD->getType();
220 ArraySize = 0;
221 MostDerivedLength = I + 1;
222 IsArray = false;
223 } else {
224 // Path[I] describes a base class.
225 ArraySize = 0;
226 IsArray = false;
227 }
228 }
229 return MostDerivedLength;
230 }
231
232 /// A path from a glvalue to a subobject of that glvalue.
233 struct SubobjectDesignator {
234 /// True if the subobject was named in a manner not supported by C++11. Such
235 /// lvalues can still be folded, but they are not core constant expressions
236 /// and we cannot perform lvalue-to-rvalue conversions on them.
237 unsigned Invalid : 1;
238
239 /// Is this a pointer one past the end of an object?
240 unsigned IsOnePastTheEnd : 1;
241
242 /// Indicator of whether the first entry is an unsized array.
243 unsigned FirstEntryIsAnUnsizedArray : 1;
244
245 /// Indicator of whether the most-derived object is an array element.
246 unsigned MostDerivedIsArrayElement : 1;
247
248 /// The length of the path to the most-derived object of which this is a
249 /// subobject.
250 unsigned MostDerivedPathLength : 28;
251
252 /// The size of the array of which the most-derived object is an element.
253 /// This will always be 0 if the most-derived object is not an array
254 /// element. 0 is not an indicator of whether or not the most-derived object
255 /// is an array, however, because 0-length arrays are allowed.
256 ///
257 /// If the current array is an unsized array, the value of this is
258 /// undefined.
259 uint64_t MostDerivedArraySize;
260
261 /// The type of the most derived object referred to by this address.
262 QualType MostDerivedType;
263
264 typedef APValue::LValuePathEntry PathEntry;
265
266 /// The entries on the path from the glvalue to the designated subobject.
267 SmallVector<PathEntry, 8> Entries;
268
269 SubobjectDesignator() : Invalid(true) {}
270
271 explicit SubobjectDesignator(QualType T)
272 : Invalid(false), IsOnePastTheEnd(false),
273 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
274 MostDerivedPathLength(0), MostDerivedArraySize(0),
275 MostDerivedType(T) {}
276
277 SubobjectDesignator(ASTContext &Ctx, const APValue &V)
278 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
279 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
280 MostDerivedPathLength(0), MostDerivedArraySize(0) {
281 assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
282 if (!Invalid) {
283 IsOnePastTheEnd = V.isLValueOnePastTheEnd();
284 ArrayRef<PathEntry> VEntries = V.getLValuePath();
285 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
286 if (V.getLValueBase()) {
287 bool IsArray = false;
288 bool FirstIsUnsizedArray = false;
289 MostDerivedPathLength = findMostDerivedSubobject(
290 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
291 MostDerivedType, IsArray, FirstIsUnsizedArray);
292 MostDerivedIsArrayElement = IsArray;
293 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
294 }
295 }
296 }
297
298 void truncate(ASTContext &Ctx, APValue::LValueBase Base,
299 unsigned NewLength) {
300 if (Invalid)
301 return;
302
303 assert(Base && "cannot truncate path for null pointer");
304 assert(NewLength <= Entries.size() && "not a truncation");
305
306 if (NewLength == Entries.size())
307 return;
308 Entries.resize(NewLength);
309
310 bool IsArray = false;
311 bool FirstIsUnsizedArray = false;
312 MostDerivedPathLength = findMostDerivedSubobject(
313 Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray,
314 FirstIsUnsizedArray);
315 MostDerivedIsArrayElement = IsArray;
316 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray;
317 }
318
319 void setInvalid() {
320 Invalid = true;
321 Entries.clear();
322 }
323
324 /// Determine whether the most derived subobject is an array without a
325 /// known bound.
326 bool isMostDerivedAnUnsizedArray() const {
327 assert(!Invalid && "Calling this makes no sense on invalid designators");
328 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
329 }
330
331 /// Determine what the most derived array's size is. Results in an assertion
332 /// failure if the most derived array lacks a size.
333 uint64_t getMostDerivedArraySize() const {
334 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size");
335 return MostDerivedArraySize;
336 }
337
338 /// Determine whether this is a one-past-the-end pointer.
339 bool isOnePastTheEnd() const {
340 assert(!Invalid);
341 if (IsOnePastTheEnd)
342 return true;
343 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement &&
344 Entries[MostDerivedPathLength - 1].getAsArrayIndex() ==
345 MostDerivedArraySize)
346 return true;
347 return false;
348 }
349
350 /// Get the range of valid index adjustments in the form
351 /// {maximum value that can be subtracted from this pointer,
352 /// maximum value that can be added to this pointer}
353 std::pair<uint64_t, uint64_t> validIndexAdjustments() {
354 if (Invalid || isMostDerivedAnUnsizedArray())
355 return {0, 0};
356
357 // [expr.add]p4: For the purposes of these operators, a pointer to a
358 // nonarray object behaves the same as a pointer to the first element of
359 // an array of length one with the type of the object as its element type.
360 bool IsArray = MostDerivedPathLength == Entries.size() &&
361 MostDerivedIsArrayElement;
362 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
363 : (uint64_t)IsOnePastTheEnd;
364 uint64_t ArraySize =
365 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
366 return {ArrayIndex, ArraySize - ArrayIndex};
367 }
368
369 /// Check that this refers to a valid subobject.
370 bool isValidSubobject() const {
371 if (Invalid)
372 return false;
373 return !isOnePastTheEnd();
374 }
375 /// Check that this refers to a valid subobject, and if not, produce a
376 /// relevant diagnostic and set the designator as invalid.
377 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK);
378
379 /// Get the type of the designated object.
380 QualType getType(ASTContext &Ctx) const {
381 assert(!Invalid && "invalid designator has no subobject type");
382 return MostDerivedPathLength == Entries.size()
383 ? MostDerivedType
384 : Ctx.getRecordType(getAsBaseClass(Entries.back()));
385 }
386
387 /// Update this designator to refer to the first element within this array.
388 void addArrayUnchecked(const ConstantArrayType *CAT) {
389 Entries.push_back(PathEntry::ArrayIndex(0));
390
391 // This is a most-derived object.
392 MostDerivedType = CAT->getElementType();
393 MostDerivedIsArrayElement = true;
394 MostDerivedArraySize = CAT->getSize().getZExtValue();
395 MostDerivedPathLength = Entries.size();
396 }
397 /// Update this designator to refer to the first element within the array of
398 /// elements of type T. This is an array of unknown size.
399 void addUnsizedArrayUnchecked(QualType ElemTy) {
400 Entries.push_back(PathEntry::ArrayIndex(0));
401
402 MostDerivedType = ElemTy;
403 MostDerivedIsArrayElement = true;
404 // The value in MostDerivedArraySize is undefined in this case. So, set it
405 // to an arbitrary value that's likely to loudly break things if it's
406 // used.
407 MostDerivedArraySize = AssumedSizeForUnsizedArray;
408 MostDerivedPathLength = Entries.size();
409 }
410 /// Update this designator to refer to the given base or member of this
411 /// object.
412 void addDeclUnchecked(const Decl *D, bool Virtual = false) {
413 Entries.push_back(APValue::BaseOrMemberType(D, Virtual));
414
415 // If this isn't a base class, it's a new most-derived object.
416 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
417 MostDerivedType = FD->getType();
418 MostDerivedIsArrayElement = false;
419 MostDerivedArraySize = 0;
420 MostDerivedPathLength = Entries.size();
421 }
422 }
423 /// Update this designator to refer to the given complex component.
424 void addComplexUnchecked(QualType EltTy, bool Imag) {
425 Entries.push_back(PathEntry::ArrayIndex(Imag));
426
427 // This is technically a most-derived object, though in practice this
428 // is unlikely to matter.
429 MostDerivedType = EltTy;
430 MostDerivedIsArrayElement = true;
431 MostDerivedArraySize = 2;
432 MostDerivedPathLength = Entries.size();
433 }
434 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E);
435 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
436 const APSInt &N);
437 /// Add N to the address of this subobject.
438 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
439 if (Invalid || !N) return;
440 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
441 if (isMostDerivedAnUnsizedArray()) {
442 diagnoseUnsizedArrayPointerArithmetic(Info, E);
443 // Can't verify -- trust that the user is doing the right thing (or if
444 // not, trust that the caller will catch the bad behavior).
445 // FIXME: Should we reject if this overflows, at least?
446 Entries.back() = PathEntry::ArrayIndex(
447 Entries.back().getAsArrayIndex() + TruncatedN);
448 return;
449 }
450
451 // [expr.add]p4: For the purposes of these operators, a pointer to a
452 // nonarray object behaves the same as a pointer to the first element of
453 // an array of length one with the type of the object as its element type.
454 bool IsArray = MostDerivedPathLength == Entries.size() &&
455 MostDerivedIsArrayElement;
456 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex()
457 : (uint64_t)IsOnePastTheEnd;
458 uint64_t ArraySize =
459 IsArray ? getMostDerivedArraySize() : (uint64_t)1;
460
461 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
462 // Calculate the actual index in a wide enough type, so we can include
463 // it in the note.
464 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
465 (llvm::APInt&)N += ArrayIndex;
466 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
467 diagnosePointerArithmetic(Info, E, N);
468 setInvalid();
469 return;
470 }
471
472 ArrayIndex += TruncatedN;
473 assert(ArrayIndex <= ArraySize &&
474 "bounds check succeeded for out-of-bounds index");
475
476 if (IsArray)
477 Entries.back() = PathEntry::ArrayIndex(ArrayIndex);
478 else
479 IsOnePastTheEnd = (ArrayIndex != 0);
480 }
481 };
482
483 /// A scope at the end of which an object can need to be destroyed.
484 enum class ScopeKind {
485 Block,
486 FullExpression,
487 Call
488 };
489
490 /// A reference to a particular call and its arguments.
491 struct CallRef {
492 CallRef() : OrigCallee(), CallIndex(0), Version() {}
493 CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version)
494 : OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {}
495
496 explicit operator bool() const { return OrigCallee; }
497
498 /// Get the parameter that the caller initialized, corresponding to the
499 /// given parameter in the callee.
500 const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const {
501 return OrigCallee ? OrigCallee->getParamDecl(PVD->getFunctionScopeIndex())
502 : PVD;
503 }
504
505 /// The callee at the point where the arguments were evaluated. This might
506 /// be different from the actual callee (a different redeclaration, or a
507 /// virtual override), but this function's parameters are the ones that
508 /// appear in the parameter map.
509 const FunctionDecl *OrigCallee;
510 /// The call index of the frame that holds the argument values.
511 unsigned CallIndex;
512 /// The version of the parameters corresponding to this call.
513 unsigned Version;
514 };
515
516 /// A stack frame in the constexpr call stack.
517 class CallStackFrame : public interp::Frame {
518 public:
519 EvalInfo &Info;
520
521 /// Parent - The caller of this stack frame.
522 CallStackFrame *Caller;
523
524 /// Callee - The function which was called.
525 const FunctionDecl *Callee;
526
527 /// This - The binding for the this pointer in this call, if any.
528 const LValue *This;
529
530 /// Information on how to find the arguments to this call. Our arguments
531 /// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a
532 /// key and this value as the version.
533 CallRef Arguments;
534
535 /// Source location information about the default argument or default
536 /// initializer expression we're evaluating, if any.
537 CurrentSourceLocExprScope CurSourceLocExprScope;
538
539 // Note that we intentionally use std::map here so that references to
540 // values are stable.
541 typedef std::pair<const void *, unsigned> MapKeyTy;
542 typedef std::map<MapKeyTy, APValue> MapTy;
543 /// Temporaries - Temporary lvalues materialized within this stack frame.
544 MapTy Temporaries;
545
546 /// CallLoc - The location of the call expression for this call.
547 SourceLocation CallLoc;
548
549 /// Index - The call index of this call.
550 unsigned Index;
551
552 /// The stack of integers for tracking version numbers for temporaries.
553 SmallVector<unsigned, 2> TempVersionStack = {1};
554 unsigned CurTempVersion = TempVersionStack.back();
555
556 unsigned getTempVersion() const { return TempVersionStack.back(); }
557
558 void pushTempVersion() {
559 TempVersionStack.push_back(++CurTempVersion);
560 }
561
562 void popTempVersion() {
563 TempVersionStack.pop_back();
564 }
565
566 CallRef createCall(const FunctionDecl *Callee) {
567 return {Callee, Index, ++CurTempVersion};
568 }
569
570 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact
571 // on the overall stack usage of deeply-recursing constexpr evaluations.
572 // (We should cache this map rather than recomputing it repeatedly.)
573 // But let's try this and see how it goes; we can look into caching the map
574 // as a later change.
575
576 /// LambdaCaptureFields - Mapping from captured variables/this to
577 /// corresponding data members in the closure class.
578 llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
579 FieldDecl *LambdaThisCaptureField;
580
581 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
582 const FunctionDecl *Callee, const LValue *This,
583 CallRef Arguments);
584 ~CallStackFrame();
585
586 // Return the temporary for Key whose version number is Version.
587 APValue *getTemporary(const void *Key, unsigned Version) {
588 MapKeyTy KV(Key, Version);
589 auto LB = Temporaries.lower_bound(KV);
590 if (LB != Temporaries.end() && LB->first == KV)
591 return &LB->second;
592 // Pair (Key,Version) wasn't found in the map. Check that no elements
593 // in the map have 'Key' as their key.
594 assert((LB == Temporaries.end() || LB->first.first != Key) &&
595 (LB == Temporaries.begin() || std::prev(LB)->first.first != Key) &&
596 "Element with key 'Key' found in map");
597 return nullptr;
598 }
599
600 // Return the current temporary for Key in the map.
601 APValue *getCurrentTemporary(const void *Key) {
602 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX));
603 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
604 return &std::prev(UB)->second;
605 return nullptr;
606 }
607
608 // Return the version number of the current temporary for Key.
609 unsigned getCurrentTemporaryVersion(const void *Key) const {
610 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX));
611 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key)
612 return std::prev(UB)->first.second;
613 return 0;
614 }
615
616 /// Allocate storage for an object of type T in this stack frame.
617 /// Populates LV with a handle to the created object. Key identifies
618 /// the temporary within the stack frame, and must not be reused without
619 /// bumping the temporary version number.
620 template<typename KeyT>
621 APValue &createTemporary(const KeyT *Key, QualType T,
622 ScopeKind Scope, LValue &LV);
623
624 /// Allocate storage for a parameter of a function call made in this frame.
625 APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);
626
627 void describe(llvm::raw_ostream &OS) override;
628
629 Frame *getCaller() const override { return Caller; }
630 SourceLocation getCallLocation() const override { return CallLoc; }
631 const FunctionDecl *getCallee() const override { return Callee; }
632
633 bool isStdFunction() const {
634 for (const DeclContext *DC = Callee; DC; DC = DC->getParent())
635 if (DC->isStdNamespace())
636 return true;
637 return false;
638 }
639
640 private:
641 APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T,
642 ScopeKind Scope);
643 };
644
645 /// Temporarily override 'this'.
646 class ThisOverrideRAII {
647 public:
648 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable)
649 : Frame(Frame), OldThis(Frame.This) {
650 if (Enable)
651 Frame.This = NewThis;
652 }
653 ~ThisOverrideRAII() {
654 Frame.This = OldThis;
655 }
656 private:
657 CallStackFrame &Frame;
658 const LValue *OldThis;
659 };
660}
661
662static bool HandleDestruction(EvalInfo &Info, const Expr *E,
663 const LValue &This, QualType ThisType);
664static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
665 APValue::LValueBase LVBase, APValue &Value,
666 QualType T);
667
668namespace {
669 /// A cleanup, and a flag indicating whether it is lifetime-extended.
670 class Cleanup {
671 llvm::PointerIntPair<APValue*, 2, ScopeKind> Value;
672 APValue::LValueBase Base;
673 QualType T;
674
675 public:
676 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T,
677 ScopeKind Scope)
678 : Value(Val, Scope), Base(Base), T(T) {}
679
680 /// Determine whether this cleanup should be performed at the end of the
681 /// given kind of scope.
682 bool isDestroyedAtEndOf(ScopeKind K) const {
683 return (int)Value.getInt() >= (int)K;
684 }
685 bool endLifetime(EvalInfo &Info, bool RunDestructors) {
686 if (RunDestructors) {
687 SourceLocation Loc;
688 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
689 Loc = VD->getLocation();
690 else if (const Expr *E = Base.dyn_cast<const Expr*>())
691 Loc = E->getExprLoc();
692 return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T);
693 }
694 *Value.getPointer() = APValue();
695 return true;
696 }
697
698 bool hasSideEffect() {
699 return T.isDestructedType();
700 }
701 };
702
703 /// A reference to an object whose construction we are currently evaluating.
704 struct ObjectUnderConstruction {
705 APValue::LValueBase Base;
706 ArrayRef<APValue::LValuePathEntry> Path;
707 friend bool operator==(const ObjectUnderConstruction &LHS,
708 const ObjectUnderConstruction &RHS) {
709 return LHS.Base == RHS.Base && LHS.Path == RHS.Path;
710 }
711 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) {
712 return llvm::hash_combine(Obj.Base, Obj.Path);
713 }
714 };
715 enum class ConstructionPhase {
716 None,
717 Bases,
718 AfterBases,
719 AfterFields,
720 Destroying,
721 DestroyingBases
722 };
723}
724
725namespace llvm {
726template<> struct DenseMapInfo<ObjectUnderConstruction> {
727 using Base = DenseMapInfo<APValue::LValueBase>;
728 static ObjectUnderConstruction getEmptyKey() {
729 return {Base::getEmptyKey(), {}}; }
730 static ObjectUnderConstruction getTombstoneKey() {
731 return {Base::getTombstoneKey(), {}};
732 }
733 static unsigned getHashValue(const ObjectUnderConstruction &Object) {
734 return hash_value(Object);
735 }
736 static bool isEqual(const ObjectUnderConstruction &LHS,
737 const ObjectUnderConstruction &RHS) {
738 return LHS == RHS;
739 }
740};
741}
742
743namespace {
744 /// A dynamically-allocated heap object.
745 struct DynAlloc {
746 /// The value of this heap-allocated object.
747 APValue Value;
748 /// The allocating expression; used for diagnostics. Either a CXXNewExpr
749 /// or a CallExpr (the latter is for direct calls to operator new inside
750 /// std::allocator<T>::allocate).
751 const Expr *AllocExpr = nullptr;
752
753 enum Kind {
754 New,
755 ArrayNew,
756 StdAllocator
757 };
758
759 /// Get the kind of the allocation. This must match between allocation
760 /// and deallocation.
761 Kind getKind() const {
762 if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr))
763 return NE->isArray() ? ArrayNew : New;
764 assert(isa<CallExpr>(AllocExpr));
765 return StdAllocator;
766 }
767 };
768
769 struct DynAllocOrder {
770 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const {
771 return L.getIndex() < R.getIndex();
772 }
773 };
774
775 /// EvalInfo - This is a private struct used by the evaluator to capture
776 /// information about a subexpression as it is folded. It retains information
777 /// about the AST context, but also maintains information about the folded
778 /// expression.
779 ///
780 /// If an expression could be evaluated, it is still possible it is not a C
781 /// "integer constant expression" or constant expression. If not, this struct
782 /// captures information about how and why not.
783 ///
784 /// One bit of information passed *into* the request for constant folding
785 /// indicates whether the subexpression is "evaluated" or not according to C
786 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can
787 /// evaluate the expression regardless of what the RHS is, but C only allows
788 /// certain things in certain situations.
789 class EvalInfo : public interp::State {
790 public:
791 ASTContext &Ctx;
792
793 /// EvalStatus - Contains information about the evaluation.
794 Expr::EvalStatus &EvalStatus;
795
796 /// CurrentCall - The top of the constexpr call stack.
797 CallStackFrame *CurrentCall;
798
799 /// CallStackDepth - The number of calls in the call stack right now.
800 unsigned CallStackDepth;
801
802 /// NextCallIndex - The next call index to assign.
803 unsigned NextCallIndex;
804
805 /// StepsLeft - The remaining number of evaluation steps we're permitted
806 /// to perform. This is essentially a limit for the number of statements
807 /// we will evaluate.
808 unsigned StepsLeft;
809
810 /// Enable the experimental new constant interpreter. If an expression is
811 /// not supported by the interpreter, an error is triggered.
812 bool EnableNewConstInterp;
813
814 /// BottomFrame - The frame in which evaluation started. This must be
815 /// initialized after CurrentCall and CallStackDepth.
816 CallStackFrame BottomFrame;
817
818 /// A stack of values whose lifetimes end at the end of some surrounding
819 /// evaluation frame.
820 llvm::SmallVector<Cleanup, 16> CleanupStack;
821
822 /// EvaluatingDecl - This is the declaration whose initializer is being
823 /// evaluated, if any.
824 APValue::LValueBase EvaluatingDecl;
825
826 enum class EvaluatingDeclKind {
827 None,
828 /// We're evaluating the construction of EvaluatingDecl.
829 Ctor,
830 /// We're evaluating the destruction of EvaluatingDecl.
831 Dtor,
832 };
833 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None;
834
835 /// EvaluatingDeclValue - This is the value being constructed for the
836 /// declaration whose initializer is being evaluated, if any.
837 APValue *EvaluatingDeclValue;
838
839 /// Set of objects that are currently being constructed.
840 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase>
841 ObjectsUnderConstruction;
842
843 /// Current heap allocations, along with the location where each was
844 /// allocated. We use std::map here because we need stable addresses
845 /// for the stored APValues.
846 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs;
847
848 /// The number of heap allocations performed so far in this evaluation.
849 unsigned NumHeapAllocs = 0;
850
851 struct EvaluatingConstructorRAII {
852 EvalInfo &EI;
853 ObjectUnderConstruction Object;
854 bool DidInsert;
855 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object,
856 bool HasBases)
857 : EI(EI), Object(Object) {
858 DidInsert =
859 EI.ObjectsUnderConstruction
860 .insert({Object, HasBases ? ConstructionPhase::Bases
861 : ConstructionPhase::AfterBases})
862 .second;
863 }
864 void finishedConstructingBases() {
865 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases;
866 }
867 void finishedConstructingFields() {
868 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields;
869 }
870 ~EvaluatingConstructorRAII() {
871 if (DidInsert) EI.ObjectsUnderConstruction.erase(Object);
872 }
873 };
874
875 struct EvaluatingDestructorRAII {
876 EvalInfo &EI;
877 ObjectUnderConstruction Object;
878 bool DidInsert;
879 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object)
880 : EI(EI), Object(Object) {
881 DidInsert = EI.ObjectsUnderConstruction
882 .insert({Object, ConstructionPhase::Destroying})
883 .second;
884 }
885 void startedDestroyingBases() {
886 EI.ObjectsUnderConstruction[Object] =
887 ConstructionPhase::DestroyingBases;
888 }
889 ~EvaluatingDestructorRAII() {
890 if (DidInsert)
891 EI.ObjectsUnderConstruction.erase(Object);
892 }
893 };
894
895 ConstructionPhase
896 isEvaluatingCtorDtor(APValue::LValueBase Base,
897 ArrayRef<APValue::LValuePathEntry> Path) {
898 return ObjectsUnderConstruction.lookup({Base, Path});
899 }
900
901 /// If we're currently speculatively evaluating, the outermost call stack
902 /// depth at which we can mutate state, otherwise 0.
903 unsigned SpeculativeEvaluationDepth = 0;
904
905 /// The current array initialization index, if we're performing array
906 /// initialization.
907 uint64_t ArrayInitIndex = -1;
908
909 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further
910 /// notes attached to it will also be stored, otherwise they will not be.
911 bool HasActiveDiagnostic;
912
913 /// Have we emitted a diagnostic explaining why we couldn't constant
914 /// fold (not just why it's not strictly a constant expression)?
915 bool HasFoldFailureDiagnostic;
916
917 /// Whether or not we're in a context where the front end requires a
918 /// constant value.
919 bool InConstantContext;
920
921 /// Whether we're checking that an expression is a potential constant
922 /// expression. If so, do not fail on constructs that could become constant
923 /// later on (such as a use of an undefined global).
924 bool CheckingPotentialConstantExpression = false;
925
926 /// Whether we're checking for an expression that has undefined behavior.
927 /// If so, we will produce warnings if we encounter an operation that is
928 /// always undefined.
929 bool CheckingForUndefinedBehavior = false;
930
931 enum EvaluationMode {
932 /// Evaluate as a constant expression. Stop if we find that the expression
933 /// is not a constant expression.
934 EM_ConstantExpression,
935
936 /// Evaluate as a constant expression. Stop if we find that the expression
937 /// is not a constant expression. Some expressions can be retried in the
938 /// optimizer if we don't constant fold them here, but in an unevaluated
939 /// context we try to fold them immediately since the optimizer never
940 /// gets a chance to look at it.
941 EM_ConstantExpressionUnevaluated,
942
943 /// Fold the expression to a constant. Stop if we hit a side-effect that
944 /// we can't model.
945 EM_ConstantFold,
946
947 /// Evaluate in any way we know how. Don't worry about side-effects that
948 /// can't be modeled.
949 EM_IgnoreSideEffects,
950 } EvalMode;
951
952 /// Are we checking whether the expression is a potential constant
953 /// expression?
954 bool checkingPotentialConstantExpression() const override {
955 return CheckingPotentialConstantExpression;
956 }
957
958 /// Are we checking an expression for overflow?
959 // FIXME: We should check for any kind of undefined or suspicious behavior
960 // in such constructs, not just overflow.
961 bool checkingForUndefinedBehavior() const override {
962 return CheckingForUndefinedBehavior;
963 }
964
965 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode)
966 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr),
967 CallStackDepth(0), NextCallIndex(1),
968 StepsLeft(C.getLangOpts().ConstexprStepLimit),
969 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp),
970 BottomFrame(*this, SourceLocation(), nullptr, nullptr, CallRef()),
971 EvaluatingDecl((const ValueDecl *)nullptr),
972 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false),
973 HasFoldFailureDiagnostic(false), InConstantContext(false),
974 EvalMode(Mode) {}
975
976 ~EvalInfo() {
977 discardCleanups();
978 }
979
980 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value,
981 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) {
982 EvaluatingDecl = Base;
983 IsEvaluatingDecl = EDK;
984 EvaluatingDeclValue = &Value;
985 }
986
987 bool CheckCallLimit(SourceLocation Loc) {
988 // Don't perform any constexpr calls (other than the call we're checking)
989 // when checking a potential constant expression.
990 if (checkingPotentialConstantExpression() && CallStackDepth > 1)
991 return false;
992 if (NextCallIndex == 0) {
993 // NextCallIndex has wrapped around.
994 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded);
995 return false;
996 }
997 if (CallStackDepth <= getLangOpts().ConstexprCallDepth)
998 return true;
999 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded)
1000 << getLangOpts().ConstexprCallDepth;
1001 return false;
1002 }
1003
1004 std::pair<CallStackFrame *, unsigned>
1005 getCallFrameAndDepth(unsigned CallIndex) {
1006 assert(CallIndex && "no call index in getCallFrameAndDepth");
1007 // We will eventually hit BottomFrame, which has Index 1, so Frame can't
1008 // be null in this loop.
1009 unsigned Depth = CallStackDepth;
1010 CallStackFrame *Frame = CurrentCall;
1011 while (Frame->Index > CallIndex) {
1012 Frame = Frame->Caller;
1013 --Depth;
1014 }
1015 if (Frame->Index == CallIndex)
1016 return {Frame, Depth};
1017 return {nullptr, 0};
1018 }
1019
1020 bool nextStep(const Stmt *S) {
1021 if (!StepsLeft) {
1022 FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded);
1023 return false;
1024 }
1025 --StepsLeft;
1026 return true;
1027 }
1028
1029 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV);
1030
1031 Optional<DynAlloc*> lookupDynamicAlloc(DynamicAllocLValue DA) {
1032 Optional<DynAlloc*> Result;
1033 auto It = HeapAllocs.find(DA);
1034 if (It != HeapAllocs.end())
1035 Result = &It->second;
1036 return Result;
1037 }
1038
1039 /// Get the allocated storage for the given parameter of the given call.
1040 APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) {
1041 CallStackFrame *Frame = getCallFrameAndDepth(Call.CallIndex).first;
1042 return Frame ? Frame->getTemporary(Call.getOrigParam(PVD), Call.Version)
1043 : nullptr;
1044 }
1045
1046 /// Information about a stack frame for std::allocator<T>::[de]allocate.
1047 struct StdAllocatorCaller {
1048 unsigned FrameIndex;
1049 QualType ElemType;
1050 explicit operator bool() const { return FrameIndex != 0; };
1051 };
1052
1053 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const {
1054 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame;
1055 Call = Call->Caller) {
1056 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee);
1057 if (!MD)
1058 continue;
1059 const IdentifierInfo *FnII = MD->getIdentifier();
1060 if (!FnII || !FnII->isStr(FnName))
1061 continue;
1062
1063 const auto *CTSD =
1064 dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent());
1065 if (!CTSD)
1066 continue;
1067
1068 const IdentifierInfo *ClassII = CTSD->getIdentifier();
1069 const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
1070 if (CTSD->isInStdNamespace() && ClassII &&
1071 ClassII->isStr("allocator") && TAL.size() >= 1 &&
1072 TAL[0].getKind() == TemplateArgument::Type)
1073 return {Call->Index, TAL[0].getAsType()};
1074 }
1075
1076 return {};
1077 }
1078
1079 void performLifetimeExtension() {
1080 // Disable the cleanups for lifetime-extended temporaries.
1081 CleanupStack.erase(std::remove_if(CleanupStack.begin(),
1082 CleanupStack.end(),
1083 [](Cleanup &C) {
1084 return !C.isDestroyedAtEndOf(
1085 ScopeKind::FullExpression);
1086 }),
1087 CleanupStack.end());
1088 }
1089
1090 /// Throw away any remaining cleanups at the end of evaluation. If any
1091 /// cleanups would have had a side-effect, note that as an unmodeled
1092 /// side-effect and return false. Otherwise, return true.
1093 bool discardCleanups() {
1094 for (Cleanup &C : CleanupStack) {
1095 if (C.hasSideEffect() && !noteSideEffect()) {
1096 CleanupStack.clear();
1097 return false;
1098 }
1099 }
1100 CleanupStack.clear();
1101 return true;
1102 }
1103
1104 private:
1105 interp::Frame *getCurrentFrame() override { return CurrentCall; }
1106 const interp::Frame *getBottomFrame() const override { return &BottomFrame; }
1107
1108 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; }
1109 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; }
1110
1111 void setFoldFailureDiagnostic(bool Flag) override {
1112 HasFoldFailureDiagnostic = Flag;
1113 }
1114
1115 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; }
1116
1117 ASTContext &getCtx() const override { return Ctx; }
1118
1119 // If we have a prior diagnostic, it will be noting that the expression
1120 // isn't a constant expression. This diagnostic is more important,
1121 // unless we require this evaluation to produce a constant expression.
1122 //
1123 // FIXME: We might want to show both diagnostics to the user in
1124 // EM_ConstantFold mode.
1125 bool hasPriorDiagnostic() override {
1126 if (!EvalStatus.Diag->empty()) {
1127 switch (EvalMode) {
1128 case EM_ConstantFold:
1129 case EM_IgnoreSideEffects:
1130 if (!HasFoldFailureDiagnostic)
1131 break;
1132 // We've already failed to fold something. Keep that diagnostic.
1133 LLVM_FALLTHROUGH;
1134 case EM_ConstantExpression:
1135 case EM_ConstantExpressionUnevaluated:
1136 setActiveDiagnostic(false);
1137 return true;
1138 }
1139 }
1140 return false;
1141 }
1142
1143 unsigned getCallStackDepth() override { return CallStackDepth; }
1144
1145 public:
1146 /// Should we continue evaluation after encountering a side-effect that we
1147 /// couldn't model?
1148 bool keepEvaluatingAfterSideEffect() {
1149 switch (EvalMode) {
1150 case EM_IgnoreSideEffects:
1151 return true;
1152
1153 case EM_ConstantExpression:
1154 case EM_ConstantExpressionUnevaluated:
1155 case EM_ConstantFold:
1156 // By default, assume any side effect might be valid in some other
1157 // evaluation of this expression from a different context.
1158 return checkingPotentialConstantExpression() ||
1159 checkingForUndefinedBehavior();
1160 }
1161 llvm_unreachable("Missed EvalMode case");
1162 }
1163
1164 /// Note that we have had a side-effect, and determine whether we should
1165 /// keep evaluating.
1166 bool noteSideEffect() {
1167 EvalStatus.HasSideEffects = true;
1168 return keepEvaluatingAfterSideEffect();
1169 }
1170
1171 /// Should we continue evaluation after encountering undefined behavior?
1172 bool keepEvaluatingAfterUndefinedBehavior() {
1173 switch (EvalMode) {
1174 case EM_IgnoreSideEffects:
1175 case EM_ConstantFold:
1176 return true;
1177
1178 case EM_ConstantExpression:
1179 case EM_ConstantExpressionUnevaluated:
1180 return checkingForUndefinedBehavior();
1181 }
1182 llvm_unreachable("Missed EvalMode case");
1183 }
1184
1185 /// Note that we hit something that was technically undefined behavior, but
1186 /// that we can evaluate past it (such as signed overflow or floating-point
1187 /// division by zero.)
1188 bool noteUndefinedBehavior() override {
1189 EvalStatus.HasUndefinedBehavior = true;
1190 return keepEvaluatingAfterUndefinedBehavior();
1191 }
1192
1193 /// Should we continue evaluation as much as possible after encountering a
1194 /// construct which can't be reduced to a value?
1195 bool keepEvaluatingAfterFailure() const override {
1196 if (!StepsLeft)
1197 return false;
1198
1199 switch (EvalMode) {
1200 case EM_ConstantExpression:
1201 case EM_ConstantExpressionUnevaluated:
1202 case EM_ConstantFold:
1203 case EM_IgnoreSideEffects:
1204 return checkingPotentialConstantExpression() ||
1205 checkingForUndefinedBehavior();
1206 }
1207 llvm_unreachable("Missed EvalMode case");
1208 }
1209
1210 /// Notes that we failed to evaluate an expression that other expressions
1211 /// directly depend on, and determine if we should keep evaluating. This
1212 /// should only be called if we actually intend to keep evaluating.
1213 ///
1214 /// Call noteSideEffect() instead if we may be able to ignore the value that
1215 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in:
1216 ///
1217 /// (Foo(), 1) // use noteSideEffect
1218 /// (Foo() || true) // use noteSideEffect
1219 /// Foo() + 1 // use noteFailure
1220 LLVM_NODISCARD bool noteFailure() {
1221 // Failure when evaluating some expression often means there is some
1222 // subexpression whose evaluation was skipped. Therefore, (because we
1223 // don't track whether we skipped an expression when unwinding after an
1224 // evaluation failure) every evaluation failure that bubbles up from a
1225 // subexpression implies that a side-effect has potentially happened. We
1226 // skip setting the HasSideEffects flag to true until we decide to
1227 // continue evaluating after that point, which happens here.
1228 bool KeepGoing = keepEvaluatingAfterFailure();
1229 EvalStatus.HasSideEffects |= KeepGoing;
1230 return KeepGoing;
1231 }
1232
1233 class ArrayInitLoopIndex {
1234 EvalInfo &Info;
1235 uint64_t OuterIndex;
1236
1237 public:
1238 ArrayInitLoopIndex(EvalInfo &Info)
1239 : Info(Info), OuterIndex(Info.ArrayInitIndex) {
1240 Info.ArrayInitIndex = 0;
1241 }
1242 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; }
1243
1244 operator uint64_t&() { return Info.ArrayInitIndex; }
1245 };
1246 };
1247
1248 /// Object used to treat all foldable expressions as constant expressions.
1249 struct FoldConstant {
1250 EvalInfo &Info;
1251 bool Enabled;
1252 bool HadNoPriorDiags;
1253 EvalInfo::EvaluationMode OldMode;
1254
1255 explicit FoldConstant(EvalInfo &Info, bool Enabled)
1256 : Info(Info),
1257 Enabled(Enabled),
1258 HadNoPriorDiags(Info.EvalStatus.Diag &&
1259 Info.EvalStatus.Diag->empty() &&
1260 !Info.EvalStatus.HasSideEffects),
1261 OldMode(Info.EvalMode) {
1262 if (Enabled)
1263 Info.EvalMode = EvalInfo::EM_ConstantFold;
1264 }
1265 void keepDiagnostics() { Enabled = false; }
1266 ~FoldConstant() {
1267 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() &&
1268 !Info.EvalStatus.HasSideEffects)
1269 Info.EvalStatus.Diag->clear();
1270 Info.EvalMode = OldMode;
1271 }
1272 };
1273
1274 /// RAII object used to set the current evaluation mode to ignore
1275 /// side-effects.
1276 struct IgnoreSideEffectsRAII {
1277 EvalInfo &Info;
1278 EvalInfo::EvaluationMode OldMode;
1279 explicit IgnoreSideEffectsRAII(EvalInfo &Info)
1280 : Info(Info), OldMode(Info.EvalMode) {
1281 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects;
1282 }
1283
1284 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; }
1285 };
1286
1287 /// RAII object used to optionally suppress diagnostics and side-effects from
1288 /// a speculative evaluation.
1289 class SpeculativeEvaluationRAII {
1290 EvalInfo *Info = nullptr;
1291 Expr::EvalStatus OldStatus;
1292 unsigned OldSpeculativeEvaluationDepth;
1293
1294 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) {
1295 Info = Other.Info;
1296 OldStatus = Other.OldStatus;
1297 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth;
1298 Other.Info = nullptr;
1299 }
1300
1301 void maybeRestoreState() {
1302 if (!Info)
1303 return;
1304
1305 Info->EvalStatus = OldStatus;
1306 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth;
1307 }
1308
1309 public:
1310 SpeculativeEvaluationRAII() = default;
1311
1312 SpeculativeEvaluationRAII(
1313 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr)
1314 : Info(&Info), OldStatus(Info.EvalStatus),
1315 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) {
1316 Info.EvalStatus.Diag = NewDiag;
1317 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1;
1318 }
1319
1320 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete;
1321 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) {
1322 moveFromAndCancel(std::move(Other));
1323 }
1324
1325 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) {
1326 maybeRestoreState();
1327 moveFromAndCancel(std::move(Other));
1328 return *this;
1329 }
1330
1331 ~SpeculativeEvaluationRAII() { maybeRestoreState(); }
1332 };
1333
1334 /// RAII object wrapping a full-expression or block scope, and handling
1335 /// the ending of the lifetime of temporaries created within it.
1336 template<ScopeKind Kind>
1337 class ScopeRAII {
1338 EvalInfo &Info;
1339 unsigned OldStackSize;
1340 public:
1341 ScopeRAII(EvalInfo &Info)
1342 : Info(Info), OldStackSize(Info.CleanupStack.size()) {
1343 // Push a new temporary version. This is needed to distinguish between
1344 // temporaries created in different iterations of a loop.
1345 Info.CurrentCall->pushTempVersion();
1346 }
1347 bool destroy(bool RunDestructors = true) {
1348 bool OK = cleanup(Info, RunDestructors, OldStackSize);
1349 OldStackSize = -1U;
1350 return OK;
1351 }
1352 ~ScopeRAII() {
1353 if (OldStackSize != -1U)
1354 destroy(false);
1355 // Body moved to a static method to encourage the compiler to inline away
1356 // instances of this class.
1357 Info.CurrentCall->popTempVersion();
1358 }
1359 private:
1360 static bool cleanup(EvalInfo &Info, bool RunDestructors,
1361 unsigned OldStackSize) {
1362 assert(OldStackSize <= Info.CleanupStack.size() &&
1363 "running cleanups out of order?");
1364
1365 // Run all cleanups for a block scope, and non-lifetime-extended cleanups
1366 // for a full-expression scope.
1367 bool Success = true;
1368 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) {
1369 if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(Kind)) {
1370 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) {
1371 Success = false;
1372 break;
1373 }
1374 }
1375 }
1376
1377 // Compact any retained cleanups.
1378 auto NewEnd = Info.CleanupStack.begin() + OldStackSize;
1379 if (Kind != ScopeKind::Block)
1380 NewEnd =
1381 std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) {
1382 return C.isDestroyedAtEndOf(Kind);
1383 });
1384 Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end());
1385 return Success;
1386 }
1387 };
1388 typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII;
1389 typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII;
1390 typedef ScopeRAII<ScopeKind::Call> CallScopeRAII;
1391}
1392
1393bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E,
1394 CheckSubobjectKind CSK) {
1395 if (Invalid)
1396 return false;
1397 if (isOnePastTheEnd()) {
1398 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject)
1399 << CSK;
1400 setInvalid();
1401 return false;
1402 }
1403 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there
1404 // must actually be at least one array element; even a VLA cannot have a
1405 // bound of zero. And if our index is nonzero, we already had a CCEDiag.
1406 return true;
1407}
1408
1409void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info,
1410 const Expr *E) {
1411 Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed);
1412 // Do not set the designator as invalid: we can represent this situation,
1413 // and correct handling of __builtin_object_size requires us to do so.
1414}
1415
1416void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info,
1417 const Expr *E,
1418 const APSInt &N) {
1419 // If we're complaining, we must be able to statically determine the size of
1420 // the most derived array.
1421 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement)
1422 Info.CCEDiag(E, diag::note_constexpr_array_index)
1423 << N << /*array*/ 0
1424 << static_cast<unsigned>(getMostDerivedArraySize());
1425 else
1426 Info.CCEDiag(E, diag::note_constexpr_array_index)
1427 << N << /*non-array*/ 1;
1428 setInvalid();
1429}
1430
1431CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
1432 const FunctionDecl *Callee, const LValue *This,
1433 CallRef Call)
1434 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This),
1435 Arguments(Call), CallLoc(CallLoc), Index(Info.NextCallIndex++) {
1436 Info.CurrentCall = this;
1437 ++Info.CallStackDepth;
1438}
1439
1440CallStackFrame::~CallStackFrame() {
1441 assert(Info.CurrentCall == this && "calls retired out of order");
1442 --Info.CallStackDepth;
1443 Info.CurrentCall = Caller;
1444}
1445
1446static bool isRead(AccessKinds AK) {
1447 return AK == AK_Read || AK == AK_ReadObjectRepresentation;
1448}
1449
1450static bool isModification(AccessKinds AK) {
1451 switch (AK) {
1452 case AK_Read:
1453 case AK_ReadObjectRepresentation:
1454 case AK_MemberCall:
1455 case AK_DynamicCast:
1456 case AK_TypeId:
1457 return false;
1458 case AK_Assign:
1459 case AK_Increment:
1460 case AK_Decrement:
1461 case AK_Construct:
1462 case AK_Destroy:
1463 return true;
1464 }
1465 llvm_unreachable("unknown access kind");
1466}
1467
1468static bool isAnyAccess(AccessKinds AK) {
1469 return isRead(AK) || isModification(AK);
1470}
1471
1472/// Is this an access per the C++ definition?
1473static bool isFormalAccess(AccessKinds AK) {
1474 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy;
1475}
1476
1477/// Is this kind of axcess valid on an indeterminate object value?
1478static bool isValidIndeterminateAccess(AccessKinds AK) {
1479 switch (AK) {
1480 case AK_Read:
1481 case AK_Increment:
1482 case AK_Decrement:
1483 // These need the object's value.
1484 return false;
1485
1486 case AK_ReadObjectRepresentation:
1487 case AK_Assign:
1488 case AK_Construct:
1489 case AK_Destroy:
1490 // Construction and destruction don't need the value.
1491 return true;
1492
1493 case AK_MemberCall:
1494 case AK_DynamicCast:
1495 case AK_TypeId:
1496 // These aren't really meaningful on scalars.
1497 return true;
1498 }
1499 llvm_unreachable("unknown access kind");
1500}
1501
1502namespace {
1503 struct ComplexValue {
1504 private:
1505 bool IsInt;
1506
1507 public:
1508 APSInt IntReal, IntImag;
1509 APFloat FloatReal, FloatImag;
1510
1511 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {}
1512
1513 void makeComplexFloat() { IsInt = false; }
1514 bool isComplexFloat() const { return !IsInt; }
1515 APFloat &getComplexFloatReal() { return FloatReal; }
1516 APFloat &getComplexFloatImag() { return FloatImag; }
1517
1518 void makeComplexInt() { IsInt = true; }
1519 bool isComplexInt() const { return IsInt; }
1520 APSInt &getComplexIntReal() { return IntReal; }
1521 APSInt &getComplexIntImag() { return IntImag; }
1522
1523 void moveInto(APValue &v) const {
1524 if (isComplexFloat())
1525 v = APValue(FloatReal, FloatImag);
1526 else
1527 v = APValue(IntReal, IntImag);
1528 }
1529 void setFrom(const APValue &v) {
1530 assert(v.isComplexFloat() || v.isComplexInt());
1531 if (v.isComplexFloat()) {
1532 makeComplexFloat();
1533 FloatReal = v.getComplexFloatReal();
1534 FloatImag = v.getComplexFloatImag();
1535 } else {
1536 makeComplexInt();
1537 IntReal = v.getComplexIntReal();
1538 IntImag = v.getComplexIntImag();
1539 }
1540 }
1541 };
1542
1543 struct LValue {
1544 APValue::LValueBase Base;
1545 CharUnits Offset;
1546 SubobjectDesignator Designator;
1547 bool IsNullPtr : 1;
1548 bool InvalidBase : 1;
1549
1550 const APValue::LValueBase getLValueBase() const { return Base; }
1551 CharUnits &getLValueOffset() { return Offset; }
1552 const CharUnits &getLValueOffset() const { return Offset; }
1553 SubobjectDesignator &getLValueDesignator() { return Designator; }
1554 const SubobjectDesignator &getLValueDesignator() const { return Designator;}
1555 bool isNullPointer() const { return IsNullPtr;}
1556
1557 unsigned getLValueCallIndex() const { return Base.getCallIndex(); }
1558 unsigned getLValueVersion() const { return Base.getVersion(); }
1559
1560 void moveInto(APValue &V) const {
1561 if (Designator.Invalid)
1562 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr);
1563 else {
1564 assert(!InvalidBase && "APValues can't handle invalid LValue bases");
1565 V = APValue(Base, Offset, Designator.Entries,
1566 Designator.IsOnePastTheEnd, IsNullPtr);
1567 }
1568 }
1569 void setFrom(ASTContext &Ctx, const APValue &V) {
1570 assert(V.isLValue() && "Setting LValue from a non-LValue?");
1571 Base = V.getLValueBase();
1572 Offset = V.getLValueOffset();
1573 InvalidBase = false;
1574 Designator = SubobjectDesignator(Ctx, V);
1575 IsNullPtr = V.isNullPointer();
1576 }
1577
1578 void set(APValue::LValueBase B, bool BInvalid = false) {
1579#ifndef NDEBUG
1580 // We only allow a few types of invalid bases. Enforce that here.
1581 if (BInvalid) {
1582 const auto *E = B.get<const Expr *>();
1583 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) &&
1584 "Unexpected type of invalid base");
1585 }
1586#endif
1587
1588 Base = B;
1589 Offset = CharUnits::fromQuantity(0);
1590 InvalidBase = BInvalid;
1591 Designator = SubobjectDesignator(getType(B));
1592 IsNullPtr = false;
1593 }
1594
1595 void setNull(ASTContext &Ctx, QualType PointerTy) {
1596 Base = (const ValueDecl *)nullptr;
1597 Offset =
1598 CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy));
1599 InvalidBase = false;
1600 Designator = SubobjectDesignator(PointerTy->getPointeeType());
1601 IsNullPtr = true;
1602 }
1603
1604 void setInvalid(APValue::LValueBase B, unsigned I = 0) {
1605 set(B, true);
1606 }
1607
1608 std::string toString(ASTContext &Ctx, QualType T) const {
1609 APValue Printable;
1610 moveInto(Printable);
1611 return Printable.getAsString(Ctx, T);
1612 }
1613
1614 private:
1615 // Check that this LValue is not based on a null pointer. If it is, produce
1616 // a diagnostic and mark the designator as invalid.
1617 template <typename GenDiagType>
1618 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) {
1619 if (Designator.Invalid)
1620 return false;
1621 if (IsNullPtr) {
1622 GenDiag();
1623 Designator.setInvalid();
1624 return false;
1625 }
1626 return true;
1627 }
1628
1629 public:
1630 bool checkNullPointer(EvalInfo &Info, const Expr *E,
1631 CheckSubobjectKind CSK) {
1632 return checkNullPointerDiagnosingWith([&Info, E, CSK] {
1633 Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK;
1634 });
1635 }
1636
1637 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E,
1638 AccessKinds AK) {
1639 return checkNullPointerDiagnosingWith([&Info, E, AK] {
1640 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
1641 });
1642 }
1643
1644 // Check this LValue refers to an object. If not, set the designator to be
1645 // invalid and emit a diagnostic.
1646 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) {
1647 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) &&
1648 Designator.checkSubobject(Info, E, CSK);
1649 }
1650
1651 void addDecl(EvalInfo &Info, const Expr *E,
1652 const Decl *D, bool Virtual = false) {
1653 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base))
1654 Designator.addDeclUnchecked(D, Virtual);
1655 }
1656 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) {
1657 if (!Designator.Entries.empty()) {
1658 Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array);
1659 Designator.setInvalid();
1660 return;
1661 }
1662 if (checkSubobject(Info, E, CSK_ArrayToPointer)) {
1663 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType());
1664 Designator.FirstEntryIsAnUnsizedArray = true;
1665 Designator.addUnsizedArrayUnchecked(ElemTy);
1666 }
1667 }
1668 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
1669 if (checkSubobject(Info, E, CSK_ArrayToPointer))
1670 Designator.addArrayUnchecked(CAT);
1671 }
1672 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
1673 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real))
1674 Designator.addComplexUnchecked(EltTy, Imag);
1675 }
1676 void clearIsNullPointer() {
1677 IsNullPtr = false;
1678 }
1679 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E,
1680 const APSInt &Index, CharUnits ElementSize) {
1681 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB,
1682 // but we're not required to diagnose it and it's valid in C++.)
1683 if (!Index)
1684 return;
1685
1686 // Compute the new offset in the appropriate width, wrapping at 64 bits.
1687 // FIXME: When compiling for a 32-bit target, we should use 32-bit
1688 // offsets.
1689 uint64_t Offset64 = Offset.getQuantity();
1690 uint64_t ElemSize64 = ElementSize.getQuantity();
1691 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
1692 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64);
1693
1694 if (checkNullPointer(Info, E, CSK_ArrayIndex))
1695 Designator.adjustIndex(Info, E, Index);
1696 clearIsNullPointer();
1697 }
1698 void adjustOffset(CharUnits N) {
1699 Offset += N;
1700 if (N.getQuantity())
1701 clearIsNullPointer();
1702 }
1703 };
1704
1705 struct MemberPtr {
1706 MemberPtr() {}
1707 explicit MemberPtr(const ValueDecl *Decl) :
1708 DeclAndIsDerivedMember(Decl, false), Path() {}
1709
1710 /// The member or (direct or indirect) field referred to by this member
1711 /// pointer, or 0 if this is a null member pointer.
1712 const ValueDecl *getDecl() const {
1713 return DeclAndIsDerivedMember.getPointer();
1714 }
1715 /// Is this actually a member of some type derived from the relevant class?
1716 bool isDerivedMember() const {
1717 return DeclAndIsDerivedMember.getInt();
1718 }
1719 /// Get the class which the declaration actually lives in.
1720 const CXXRecordDecl *getContainingRecord() const {
1721 return cast<CXXRecordDecl>(
1722 DeclAndIsDerivedMember.getPointer()->getDeclContext());
1723 }
1724
1725 void moveInto(APValue &V) const {
1726 V = APValue(getDecl(), isDerivedMember(), Path);
1727 }
1728 void setFrom(const APValue &V) {
1729 assert(V.isMemberPointer());
1730 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl());
1731 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember());
1732 Path.clear();
1733 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath();
1734 Path.insert(Path.end(), P.begin(), P.end());
1735 }
1736
1737 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating
1738 /// whether the member is a member of some class derived from the class type
1739 /// of the member pointer.
1740 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember;
1741 /// Path - The path of base/derived classes from the member declaration's
1742 /// class (exclusive) to the class type of the member pointer (inclusive).
1743 SmallVector<const CXXRecordDecl*, 4> Path;
1744
1745 /// Perform a cast towards the class of the Decl (either up or down the
1746 /// hierarchy).
1747 bool castBack(const CXXRecordDecl *Class) {
1748 assert(!Path.empty());
1749 const CXXRecordDecl *Expected;
1750 if (Path.size() >= 2)
1751 Expected = Path[Path.size() - 2];
1752 else
1753 Expected = getContainingRecord();
1754 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) {
1755 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*),
1756 // if B does not contain the original member and is not a base or
1757 // derived class of the class containing the original member, the result
1758 // of the cast is undefined.
1759 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to
1760 // (D::*). We consider that to be a language defect.
1761 return false;
1762 }
1763 Path.pop_back();
1764 return true;
1765 }
1766 /// Perform a base-to-derived member pointer cast.
1767 bool castToDerived(const CXXRecordDecl *Derived) {
1768 if (!getDecl())
1769 return true;
1770 if (!isDerivedMember()) {
1771 Path.push_back(Derived);
1772 return true;
1773 }
1774 if (!castBack(Derived))
1775 return false;
1776 if (Path.empty())
1777 DeclAndIsDerivedMember.setInt(false);
1778 return true;
1779 }
1780 /// Perform a derived-to-base member pointer cast.
1781 bool castToBase(const CXXRecordDecl *Base) {
1782 if (!getDecl())
1783 return true;
1784 if (Path.empty())
1785 DeclAndIsDerivedMember.setInt(true);
1786 if (isDerivedMember()) {
1787 Path.push_back(Base);
1788 return true;
1789 }
1790 return castBack(Base);
1791 }
1792 };
1793
1794 /// Compare two member pointers, which are assumed to be of the same type.
1795 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) {
1796 if (!LHS.getDecl() || !RHS.getDecl())
1797 return !LHS.getDecl() && !RHS.getDecl();
1798 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl())
1799 return false;
1800 return LHS.Path == RHS.Path;
1801 }
1802}
1803
1804static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E);
1805static bool EvaluateInPlace(APValue &Result, EvalInfo &Info,
1806 const LValue &This, const Expr *E,
1807 bool AllowNonLiteralTypes = false);
1808static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
1809 bool InvalidBaseOK = false);
1810static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info,
1811 bool InvalidBaseOK = false);
1812static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
1813 EvalInfo &Info);
1814static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info);
1815static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info);
1816static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
1817 EvalInfo &Info);
1818static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
1819static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
1820static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
1821 EvalInfo &Info);
1822static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
1823
1824/// Evaluate an integer or fixed point expression into an APResult.
1825static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
1826 EvalInfo &Info);
1827
1828/// Evaluate only a fixed point expression into an APResult.
1829static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
1830 EvalInfo &Info);
1831
1832//===----------------------------------------------------------------------===//
1833// Misc utilities
1834//===----------------------------------------------------------------------===//
1835
1836/// Negate an APSInt in place, converting it to a signed form if necessary, and
1837/// preserving its value (by extending by up to one bit as needed).
1838static void negateAsSigned(APSInt &Int) {
1839 if (Int.isUnsigned() || Int.isMinSignedValue()) {
1840 Int = Int.extend(Int.getBitWidth() + 1);
1841 Int.setIsSigned(true);
1842 }
1843 Int = -Int;
1844}
1845
1846template<typename KeyT>
1847APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
1848 ScopeKind Scope, LValue &LV) {
1849 unsigned Version = getTempVersion();
1850 APValue::LValueBase Base(Key, Index, Version);
1851 LV.set(Base);
1852 return createLocal(Base, Key, T, Scope);
1853}
1854
1855/// Allocate storage for a parameter of a function call made in this frame.
1856APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
1857 LValue &LV) {
1858 assert(Args.CallIndex == Index && "creating parameter in wrong frame");
1859 APValue::LValueBase Base(PVD, Index, Args.Version);
1860 LV.set(Base);
1861 // We always destroy parameters at the end of the call, even if we'd allow
1862 // them to live to the end of the full-expression at runtime, in order to
1863 // give portable results and match other compilers.
1864 return createLocal(Base, PVD, PVD->getType(), ScopeKind::Call);
1865}
1866
1867APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key,
1868 QualType T, ScopeKind Scope) {
1869 assert(Base.getCallIndex() == Index && "lvalue for wrong frame");
1870 unsigned Version = Base.getVersion();
1871 APValue &Result = Temporaries[MapKeyTy(Key, Version)];
1872 assert(Result.isAbsent() && "local created multiple times");
1873
1874 // If we're creating a local immediately in the operand of a speculative
1875 // evaluation, don't register a cleanup to be run outside the speculative
1876 // evaluation context, since we won't actually be able to initialize this
1877 // object.
1878 if (Index <= Info.SpeculativeEvaluationDepth) {
1879 if (T.isDestructedType())
1880 Info.noteSideEffect();
1881 } else {
1882 Info.CleanupStack.push_back(Cleanup(&Result, Base, T, Scope));
1883 }
1884 return Result;
1885}
1886
1887APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) {
1888 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) {
1889 FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded);
1890 return nullptr;
1891 }
1892
1893 DynamicAllocLValue DA(NumHeapAllocs++);
1894 LV.set(APValue::LValueBase::getDynamicAlloc(DA, T));
1895 auto Result = HeapAllocs.emplace(std::piecewise_construct,
1896 std::forward_as_tuple(DA), std::tuple<>());
1897 assert(Result.second && "reused a heap alloc index?");
1898 Result.first->second.AllocExpr = E;
1899 return &Result.first->second.Value;
1900}
1901
1902/// Produce a string describing the given constexpr call.
1903void CallStackFrame::describe(raw_ostream &Out) {
1904 unsigned ArgIndex = 0;
1905 bool IsMemberCall = isa<CXXMethodDecl>(Callee) &&
1906 !isa<CXXConstructorDecl>(Callee) &&
1907 cast<CXXMethodDecl>(Callee)->isInstance();
1908
1909 if (!IsMemberCall)
1910 Out << *Callee << '(';
1911
1912 if (This && IsMemberCall) {
1913 APValue Val;
1914 This->moveInto(Val);
1915 Val.printPretty(Out, Info.Ctx,
1916 This->Designator.MostDerivedType);
1917 // FIXME: Add parens around Val if needed.
1918 Out << "->" << *Callee << '(';
1919 IsMemberCall = false;
1920 }
1921
1922 for (FunctionDecl::param_const_iterator I = Callee->param_begin(),
1923 E = Callee->param_end(); I != E; ++I, ++ArgIndex) {
1924 if (ArgIndex > (unsigned)IsMemberCall)
1925 Out << ", ";
1926
1927 const ParmVarDecl *Param = *I;
1928 APValue *V = Info.getParamSlot(Arguments, Param);
1929 if (V)
1930 V->printPretty(Out, Info.Ctx, Param->getType());
1931 else
1932 Out << "<...>";
1933
1934 if (ArgIndex == 0 && IsMemberCall)
1935 Out << "->" << *Callee << '(';
1936 }
1937
1938 Out << ')';
1939}
1940
1941/// Evaluate an expression to see if it had side-effects, and discard its
1942/// result.
1943/// \return \c true if the caller should keep evaluating.
1944static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) {
1945 assert(!E->isValueDependent());
1946 APValue Scratch;
1947 if (!Evaluate(Scratch, Info, E))
1948 // We don't need the value, but we might have skipped a side effect here.
1949 return Info.noteSideEffect();
1950 return true;
1951}
1952
1953/// Should this call expression be treated as a string literal?
1954static bool IsStringLiteralCall(const CallExpr *E) {
1955 unsigned Builtin = E->getBuiltinCallee();
1956 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
1957 Builtin == Builtin::BI__builtin___NSStringMakeConstantString);
1958}
1959
1960static bool IsGlobalLValue(APValue::LValueBase B) {
1961 // C++11 [expr.const]p3 An address constant expression is a prvalue core
1962 // constant expression of pointer type that evaluates to...
1963
1964 // ... a null pointer value, or a prvalue core constant expression of type
1965 // std::nullptr_t.
1966 if (!B) return true;
1967
1968 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
1969 // ... the address of an object with static storage duration,
1970 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
1971 return VD->hasGlobalStorage();
1972 if (isa<TemplateParamObjectDecl>(D))
1973 return true;
1974 // ... the address of a function,
1975 // ... the address of a GUID [MS extension],
1976 return isa<FunctionDecl>(D) || isa<MSGuidDecl>(D);
1977 }
1978
1979 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>())
1980 return true;
1981
1982 const Expr *E = B.get<const Expr*>();
1983 switch (E->getStmtClass()) {
1984 default:
1985 return false;
1986 case Expr::CompoundLiteralExprClass: {
1987 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
1988 return CLE->isFileScope() && CLE->isLValue();
1989 }
1990 case Expr::MaterializeTemporaryExprClass:
1991 // A materialized temporary might have been lifetime-extended to static
1992 // storage duration.
1993 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
1994 // A string literal has static storage duration.
1995 case Expr::StringLiteralClass:
1996 case Expr::PredefinedExprClass:
1997 case Expr::ObjCStringLiteralClass:
1998 case Expr::ObjCEncodeExprClass:
1999 return true;
2000 case Expr::ObjCBoxedExprClass:
2001 return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer();
2002 case Expr::CallExprClass:
2003 return IsStringLiteralCall(cast<CallExpr>(E));
2004 // For GCC compatibility, &&label has static storage duration.
2005 case Expr::AddrLabelExprClass:
2006 return true;
2007 // A Block literal expression may be used as the initialization value for
2008 // Block variables at global or local static scope.
2009 case Expr::BlockExprClass:
2010 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures();
2011 case Expr::ImplicitValueInitExprClass:
2012 // FIXME:
2013 // We can never form an lvalue with an implicit value initialization as its
2014 // base through expression evaluation, so these only appear in one case: the
2015 // implicit variable declaration we invent when checking whether a constexpr
2016 // constructor can produce a constant expression. We must assume that such
2017 // an expression might be a global lvalue.
2018 return true;
2019 }
2020}
2021
2022static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) {
2023 return LVal.Base.dyn_cast<const ValueDecl*>();
2024}
2025
2026static bool IsLiteralLValue(const LValue &Value) {
2027 if (Value.getLValueCallIndex())
2028 return false;
2029 const Expr *E = Value.Base.dyn_cast<const Expr*>();
2030 return E && !isa<MaterializeTemporaryExpr>(E);
2031}
2032
2033static bool IsWeakLValue(const LValue &Value) {
2034 const ValueDecl *Decl = GetLValueBaseDecl(Value);
2035 return Decl && Decl->isWeak();
2036}
2037
2038static bool isZeroSized(const LValue &Value) {
2039 const ValueDecl *Decl = GetLValueBaseDecl(Value);
2040 if (Decl && isa<VarDecl>(Decl)) {
2041 QualType Ty = Decl->getType();
2042 if (Ty->isArrayType())
2043 return Ty->isIncompleteType() ||
2044 Decl->getASTContext().getTypeSize(Ty) == 0;
2045 }
2046 return false;
2047}
2048
2049static bool HasSameBase(const LValue &A, const LValue &B) {
2050 if (!A.getLValueBase())
2051 return !B.getLValueBase();
2052 if (!B.getLValueBase())
2053 return false;
2054
2055 if (A.getLValueBase().getOpaqueValue() !=
2056 B.getLValueBase().getOpaqueValue())
2057 return false;
2058
2059 return A.getLValueCallIndex() == B.getLValueCallIndex() &&
2060 A.getLValueVersion() == B.getLValueVersion();
2061}
2062
2063static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) {
2064 assert(Base && "no location for a null lvalue");
2065 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2066
2067 // For a parameter, find the corresponding call stack frame (if it still
2068 // exists), and point at the parameter of the function definition we actually
2069 // invoked.
2070 if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(VD)) {
2071 unsigned Idx = PVD->getFunctionScopeIndex();
2072 for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) {
2073 if (F->Arguments.CallIndex == Base.getCallIndex() &&
2074 F->Arguments.Version == Base.getVersion() && F->Callee &&
2075 Idx < F->Callee->getNumParams()) {
2076 VD = F->Callee->getParamDecl(Idx);
2077 break;
2078 }
2079 }
2080 }
2081
2082 if (VD)
2083 Info.Note(VD->getLocation(), diag::note_declared_at);
2084 else if (const Expr *E = Base.dyn_cast<const Expr*>())
2085 Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here);
2086 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) {
2087 // FIXME: Produce a note for dangling pointers too.
2088 if (Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA))
2089 Info.Note((*Alloc)->AllocExpr->getExprLoc(),
2090 diag::note_constexpr_dynamic_alloc_here);
2091 }
2092 // We have no information to show for a typeid(T) object.
2093}
2094
2095enum class CheckEvaluationResultKind {
2096 ConstantExpression,
2097 FullyInitialized,
2098};
2099
2100/// Materialized temporaries that we've already checked to determine if they're
2101/// initializsed by a constant expression.
2102using CheckedTemporaries =
2103 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>;
2104
2105static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2106 EvalInfo &Info, SourceLocation DiagLoc,
2107 QualType Type, const APValue &Value,
2108 ConstantExprKind Kind,
2109 SourceLocation SubobjectLoc,
2110 CheckedTemporaries &CheckedTemps);
2111
2112/// Check that this reference or pointer core constant expression is a valid
2113/// value for an address or reference constant expression. Return true if we
2114/// can fold this expression, whether or not it's a constant expression.
2115static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc,
2116 QualType Type, const LValue &LVal,
2117 ConstantExprKind Kind,
2118 CheckedTemporaries &CheckedTemps) {
2119 bool IsReferenceType = Type->isReferenceType();
2120
2121 APValue::LValueBase Base = LVal.getLValueBase();
2122 const SubobjectDesignator &Designator = LVal.getLValueDesignator();
2123
2124 const Expr *BaseE = Base.dyn_cast<const Expr *>();
2125 const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>();
2126
2127 // Additional restrictions apply in a template argument. We only enforce the
2128 // C++20 restrictions here; additional syntactic and semantic restrictions
2129 // are applied elsewhere.
2130 if (isTemplateArgument(Kind)) {
2131 int InvalidBaseKind = -1;
2132 StringRef Ident;
2133 if (Base.is<TypeInfoLValue>())
2134 InvalidBaseKind = 0;
2135 else if (isa_and_nonnull<StringLiteral>(BaseE))
2136 InvalidBaseKind = 1;
2137 else if (isa_and_nonnull<MaterializeTemporaryExpr>(BaseE) ||
2138 isa_and_nonnull<LifetimeExtendedTemporaryDecl>(BaseVD))
2139 InvalidBaseKind = 2;
2140 else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(BaseE)) {
2141 InvalidBaseKind = 3;
2142 Ident = PE->getIdentKindName();
2143 }
2144
2145 if (InvalidBaseKind != -1) {
2146 Info.FFDiag(Loc, diag::note_constexpr_invalid_template_arg)
2147 << IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind
2148 << Ident;
2149 return false;
2150 }
2151 }
2152
2153 if (auto *FD = dyn_cast_or_null<FunctionDecl>(BaseVD)) {
2154 if (FD->isConsteval()) {
2155 Info.FFDiag(Loc, diag::note_consteval_address_accessible)
2156 << !Type->isAnyPointerType();
2157 Info.Note(FD->getLocation(), diag::note_declared_at);
2158 return false;
2159 }
2160 }
2161
2162 // Check that the object is a global. Note that the fake 'this' object we
2163 // manufacture when checking potential constant expressions is conservatively
2164 // assumed to be global here.
2165 if (!IsGlobalLValue(Base)) {
2166 if (Info.getLangOpts().CPlusPlus11) {
2167 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>();
2168 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1)
2169 << IsReferenceType << !Designator.Entries.empty()
2170 << !!VD << VD;
2171
2172 auto *VarD = dyn_cast_or_null<VarDecl>(VD);
2173 if (VarD && VarD->isConstexpr()) {
2174 // Non-static local constexpr variables have unintuitive semantics:
2175 // constexpr int a = 1;
2176 // constexpr const int *p = &a;
2177 // ... is invalid because the address of 'a' is not constant. Suggest
2178 // adding a 'static' in this case.
2179 Info.Note(VarD->getLocation(), diag::note_constexpr_not_static)
2180 << VarD
2181 << FixItHint::CreateInsertion(VarD->getBeginLoc(), "static ");
2182 } else {
2183 NoteLValueLocation(Info, Base);
2184 }
2185 } else {
2186 Info.FFDiag(Loc);
2187 }
2188 // Don't allow references to temporaries to escape.
2189 return false;
2190 }
2191 assert((Info.checkingPotentialConstantExpression() ||
2192 LVal.getLValueCallIndex() == 0) &&
2193 "have call index for global lvalue");
2194
2195 if (Base.is<DynamicAllocLValue>()) {
2196 Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc)
2197 << IsReferenceType << !Designator.Entries.empty();
2198 NoteLValueLocation(Info, Base);
2199 return false;
2200 }
2201
2202 if (BaseVD) {
2203 if (const VarDecl *Var = dyn_cast<const VarDecl>(BaseVD)) {
2204 // Check if this is a thread-local variable.
2205 if (Var->getTLSKind())
2206 // FIXME: Diagnostic!
2207 return false;
2208
2209 // A dllimport variable never acts like a constant, unless we're
2210 // evaluating a value for use only in name mangling.
2211 if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>())
2212 // FIXME: Diagnostic!
2213 return false;
2214 }
2215 if (const auto *FD = dyn_cast<const FunctionDecl>(BaseVD)) {
2216 // __declspec(dllimport) must be handled very carefully:
2217 // We must never initialize an expression with the thunk in C++.
2218 // Doing otherwise would allow the same id-expression to yield
2219 // different addresses for the same function in different translation
2220 // units. However, this means that we must dynamically initialize the
2221 // expression with the contents of the import address table at runtime.
2222 //
2223 // The C language has no notion of ODR; furthermore, it has no notion of
2224 // dynamic initialization. This means that we are permitted to
2225 // perform initialization with the address of the thunk.
2226 if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) &&
2227 FD->hasAttr<DLLImportAttr>())
2228 // FIXME: Diagnostic!
2229 return false;
2230 }
2231 } else if (const auto *MTE =
2232 dyn_cast_or_null<MaterializeTemporaryExpr>(BaseE)) {
2233 if (CheckedTemps.insert(MTE).second) {
2234 QualType TempType = getType(Base);
2235 if (TempType.isDestructedType()) {
2236 Info.FFDiag(MTE->getExprLoc(),
2237 diag::note_constexpr_unsupported_temporary_nontrivial_dtor)
2238 << TempType;
2239 return false;
2240 }
2241
2242 APValue *V = MTE->getOrCreateValue(false);
2243 assert(V && "evasluation result refers to uninitialised temporary");
2244 if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2245 Info, MTE->getExprLoc(), TempType, *V,
2246 Kind, SourceLocation(), CheckedTemps))
2247 return false;
2248 }
2249 }
2250
2251 // Allow address constant expressions to be past-the-end pointers. This is
2252 // an extension: the standard requires them to point to an object.
2253 if (!IsReferenceType)
2254 return true;
2255
2256 // A reference constant expression must refer to an object.
2257 if (!Base) {
2258 // FIXME: diagnostic
2259 Info.CCEDiag(Loc);
2260 return true;
2261 }
2262
2263 // Does this refer one past the end of some object?
2264 if (!Designator.Invalid && Designator.isOnePastTheEnd()) {
2265 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1)
2266 << !Designator.Entries.empty() << !!BaseVD << BaseVD;
2267 NoteLValueLocation(Info, Base);
2268 }
2269
2270 return true;
2271}
2272
2273/// Member pointers are constant expressions unless they point to a
2274/// non-virtual dllimport member function.
2275static bool CheckMemberPointerConstantExpression(EvalInfo &Info,
2276 SourceLocation Loc,
2277 QualType Type,
2278 const APValue &Value,
2279 ConstantExprKind Kind) {
2280 const ValueDecl *Member = Value.getMemberPointerDecl();
2281 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member);
2282 if (!FD)
2283 return true;
2284 if (FD->isConsteval()) {
2285 Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0;
2286 Info.Note(FD->getLocation(), diag::note_declared_at);
2287 return false;
2288 }
2289 return isForManglingOnly(Kind) || FD->isVirtual() ||
2290 !FD->hasAttr<DLLImportAttr>();
2291}
2292
2293/// Check that this core constant expression is of literal type, and if not,
2294/// produce an appropriate diagnostic.
2295static bool CheckLiteralType(EvalInfo &Info, const Expr *E,
2296 const LValue *This = nullptr) {
2297 if (!E->isRValue() || E->getType()->isLiteralType(Info.Ctx))
2298 return true;
2299
2300 // C++1y: A constant initializer for an object o [...] may also invoke
2301 // constexpr constructors for o and its subobjects even if those objects
2302 // are of non-literal class types.
2303 //
2304 // C++11 missed this detail for aggregates, so classes like this:
2305 // struct foo_t { union { int i; volatile int j; } u; };
2306 // are not (obviously) initializable like so:
2307 // __attribute__((__require_constant_initialization__))
2308 // static const foo_t x = {{0}};
2309 // because "i" is a subobject with non-literal initialization (due to the
2310 // volatile member of the union). See:
2311 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677
2312 // Therefore, we use the C++1y behavior.
2313 if (This && Info.EvaluatingDecl == This->getLValueBase())
2314 return true;
2315
2316 // Prvalue constant expressions must be of literal types.
2317 if (Info.getLangOpts().CPlusPlus11)
2318 Info.FFDiag(E, diag::note_constexpr_nonliteral)
2319 << E->getType();
2320 else
2321 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2322 return false;
2323}
2324
2325static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
2326 EvalInfo &Info, SourceLocation DiagLoc,
2327 QualType Type, const APValue &Value,
2328 ConstantExprKind Kind,
2329 SourceLocation SubobjectLoc,
2330 CheckedTemporaries &CheckedTemps) {
2331 if (!Value.hasValue()) {
2332 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
2333 << true << Type;
2334 if (SubobjectLoc.isValid())
2335 Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here);
2336 return false;
2337 }
2338
2339 // We allow _Atomic(T) to be initialized from anything that T can be
2340 // initialized from.
2341 if (const AtomicType *AT = Type->getAs<AtomicType>())
2342 Type = AT->getValueType();
2343
2344 // Core issue 1454: For a literal constant expression of array or class type,
2345 // each subobject of its value shall have been initialized by a constant
2346 // expression.
2347 if (Value.isArray()) {
2348 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType();
2349 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) {
2350 if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2351 Value.getArrayInitializedElt(I), Kind,
2352 SubobjectLoc, CheckedTemps))
2353 return false;
2354 }
2355 if (!Value.hasArrayFiller())
2356 return true;
2357 return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy,
2358 Value.getArrayFiller(), Kind, SubobjectLoc,
2359 CheckedTemps);
2360 }
2361 if (Value.isUnion() && Value.getUnionField()) {
2362 return CheckEvaluationResult(
2363 CERK, Info, DiagLoc, Value.getUnionField()->getType(),
2364 Value.getUnionValue(), Kind, Value.getUnionField()->getLocation(),
2365 CheckedTemps);
2366 }
2367 if (Value.isStruct()) {
2368 RecordDecl *RD = Type->castAs<RecordType>()->getDecl();
2369 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
2370 unsigned BaseIndex = 0;
2371 for (const CXXBaseSpecifier &BS : CD->bases()) {
2372 if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
2373 Value.getStructBase(BaseIndex), Kind,
2374 BS.getBeginLoc(), CheckedTemps))
2375 return false;
2376 ++BaseIndex;
2377 }
2378 }
2379 for (const auto *I : RD->fields()) {
2380 if (I->isUnnamedBitfield())
2381 continue;
2382
2383 if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(),
2384 Value.getStructField(I->getFieldIndex()),
2385 Kind, I->getLocation(), CheckedTemps))
2386 return false;
2387 }
2388 }
2389
2390 if (Value.isLValue() &&
2391 CERK == CheckEvaluationResultKind::ConstantExpression) {
2392 LValue LVal;
2393 LVal.setFrom(Info.Ctx, Value);
2394 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Kind,
2395 CheckedTemps);
2396 }
2397
2398 if (Value.isMemberPointer() &&
2399 CERK == CheckEvaluationResultKind::ConstantExpression)
2400 return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Kind);
2401
2402 // Everything else is fine.
2403 return true;
2404}
2405
2406/// Check that this core constant expression value is a valid value for a
2407/// constant expression. If not, report an appropriate diagnostic. Does not
2408/// check that the expression is of literal type.
2409static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc,
2410 QualType Type, const APValue &Value,
2411 ConstantExprKind Kind) {
2412 // Nothing to check for a constant expression of type 'cv void'.
2413 if (Type->isVoidType())
2414 return true;
2415
2416 CheckedTemporaries CheckedTemps;
2417 return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression,
2418 Info, DiagLoc, Type, Value, Kind,
2419 SourceLocation(), CheckedTemps);
2420}
2421
2422/// Check that this evaluated value is fully-initialized and can be loaded by
2423/// an lvalue-to-rvalue conversion.
2424static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc,
2425 QualType Type, const APValue &Value) {
2426 CheckedTemporaries CheckedTemps;
2427 return CheckEvaluationResult(
2428 CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value,
2429 ConstantExprKind::Normal, SourceLocation(), CheckedTemps);
2430}
2431
2432/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless
2433/// "the allocated storage is deallocated within the evaluation".
2434static bool CheckMemoryLeaks(EvalInfo &Info) {
2435 if (!Info.HeapAllocs.empty()) {
2436 // We can still fold to a constant despite a compile-time memory leak,
2437 // so long as the heap allocation isn't referenced in the result (we check
2438 // that in CheckConstantExpression).
2439 Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr,
2440 diag::note_constexpr_memory_leak)
2441 << unsigned(Info.HeapAllocs.size() - 1);
2442 }
2443 return true;
2444}
2445
2446static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) {
2447 // A null base expression indicates a null pointer. These are always
2448 // evaluatable, and they are false unless the offset is zero.
2449 if (!Value.getLValueBase()) {
2450 Result = !Value.getLValueOffset().isZero();
2451 return true;
2452 }
2453
2454 // We have a non-null base. These are generally known to be true, but if it's
2455 // a weak declaration it can be null at runtime.
2456 Result = true;
2457 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>();
2458 return !Decl || !Decl->isWeak();
2459}
2460
2461static bool HandleConversionToBool(const APValue &Val, bool &Result) {
2462 switch (Val.getKind()) {
2463 case APValue::None:
2464 case APValue::Indeterminate:
2465 return false;
2466 case APValue::Int:
2467 Result = Val.getInt().getBoolValue();
2468 return true;
2469 case APValue::FixedPoint:
2470 Result = Val.getFixedPoint().getBoolValue();
2471 return true;
2472 case APValue::Float:
2473 Result = !Val.getFloat().isZero();
2474 return true;
2475 case APValue::ComplexInt:
2476 Result = Val.getComplexIntReal().getBoolValue() ||
2477 Val.getComplexIntImag().getBoolValue();
2478 return true;
2479 case APValue::ComplexFloat:
2480 Result = !Val.getComplexFloatReal().isZero() ||
2481 !Val.getComplexFloatImag().isZero();
2482 return true;
2483 case APValue::LValue:
2484 return EvalPointerValueAsBool(Val, Result);
2485 case APValue::MemberPointer:
2486 Result = Val.getMemberPointerDecl();
2487 return true;
2488 case APValue::Vector:
2489 case APValue::Array:
2490 case APValue::Struct:
2491 case APValue::Union:
2492 case APValue::AddrLabelDiff:
2493 return false;
2494 }
2495
2496 llvm_unreachable("unknown APValue kind");
2497}
2498
2499static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result,
2500 EvalInfo &Info) {
2501 assert(!E->isValueDependent());
2502 assert(E->isRValue() && "missing lvalue-to-rvalue conv in bool condition");
2503 APValue Val;
2504 if (!Evaluate(Val, Info, E))
2505 return false;
2506 return HandleConversionToBool(Val, Result);
2507}
2508
2509template<typename T>
2510static bool HandleOverflow(EvalInfo &Info, const Expr *E,
2511 const T &SrcValue, QualType DestType) {
2512 Info.CCEDiag(E, diag::note_constexpr_overflow)
2513 << SrcValue << DestType;
2514 return Info.noteUndefinedBehavior();
2515}
2516
2517static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E,
2518 QualType SrcType, const APFloat &Value,
2519 QualType DestType, APSInt &Result) {
2520 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2521 // Determine whether we are converting to unsigned or signed.
2522 bool DestSigned = DestType->isSignedIntegerOrEnumerationType();
2523
2524 Result = APSInt(DestWidth, !DestSigned);
2525 bool ignored;
2526 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored)
2527 & APFloat::opInvalidOp)
2528 return HandleOverflow(Info, E, Value, DestType);
2529 return true;
2530}
2531
2532/// Get rounding mode used for evaluation of the specified expression.
2533/// \param[out] DynamicRM Is set to true is the requested rounding mode is
2534/// dynamic.
2535/// If rounding mode is unknown at compile time, still try to evaluate the
2536/// expression. If the result is exact, it does not depend on rounding mode.
2537/// So return "tonearest" mode instead of "dynamic".
2538static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E,
2539 bool &DynamicRM) {
2540 llvm::RoundingMode RM =
2541 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).getRoundingMode();
2542 DynamicRM = (RM == llvm::RoundingMode::Dynamic);
2543 if (DynamicRM)
2544 RM = llvm::RoundingMode::NearestTiesToEven;
2545 return RM;
2546}
2547
2548/// Check if the given evaluation result is allowed for constant evaluation.
2549static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E,
2550 APFloat::opStatus St) {
2551 // In a constant context, assume that any dynamic rounding mode or FP
2552 // exception state matches the default floating-point environment.
2553 if (Info.InConstantContext)
2554 return true;
2555
2556 FPOptions FPO = E->getFPFeaturesInEffect(Info.Ctx.getLangOpts());
2557 if ((St & APFloat::opInexact) &&
2558 FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) {
2559 // Inexact result means that it depends on rounding mode. If the requested
2560 // mode is dynamic, the evaluation cannot be made in compile time.
2561 Info.FFDiag(E, diag::note_constexpr_dynamic_rounding);
2562 return false;
2563 }
2564
2565 if ((St != APFloat::opOK) &&
2566 (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic ||
2567 FPO.getFPExceptionMode() != LangOptions::FPE_Ignore ||
2568 FPO.getAllowFEnvAccess())) {
2569 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
2570 return false;
2571 }
2572
2573 if ((St & APFloat::opStatus::opInvalidOp) &&
2574 FPO.getFPExceptionMode() != LangOptions::FPE_Ignore) {
2575 // There is no usefully definable result.
2576 Info.FFDiag(E);
2577 return false;
2578 }
2579
2580 // FIXME: if:
2581 // - evaluation triggered other FP exception, and
2582 // - exception mode is not "ignore", and
2583 // - the expression being evaluated is not a part of global variable
2584 // initializer,
2585 // the evaluation probably need to be rejected.
2586 return true;
2587}
2588
2589static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E,
2590 QualType SrcType, QualType DestType,
2591 APFloat &Result) {
2592 assert(isa<CastExpr>(E) || isa<CompoundAssignOperator>(E));
2593 bool DynamicRM;
2594 llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
2595 APFloat::opStatus St;
2596 APFloat Value = Result;
2597 bool ignored;
2598 St = Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), RM, &ignored);
2599 return checkFloatingPointResult(Info, E, St);
2600}
2601
2602static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E,
2603 QualType DestType, QualType SrcType,
2604 const APSInt &Value) {
2605 unsigned DestWidth = Info.Ctx.getIntWidth(DestType);
2606 // Figure out if this is a truncate, extend or noop cast.
2607 // If the input is signed, do a sign extend, noop, or truncate.
2608 APSInt Result = Value.extOrTrunc(DestWidth);
2609 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType());
2610 if (DestType->isBooleanType())
2611 Result = Value.getBoolValue();
2612 return Result;
2613}
2614
2615static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E,
2616 const FPOptions FPO,
2617 QualType SrcType, const APSInt &Value,
2618 QualType DestType, APFloat &Result) {
2619 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1);
2620 APFloat::opStatus St = Result.convertFromAPInt(Value, Value.isSigned(),
2621 APFloat::rmNearestTiesToEven);
2622 if (!Info.InConstantContext && St != llvm::APFloatBase::opOK &&
2623 FPO.isFPConstrained()) {
2624 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
2625 return false;
2626 }
2627 return true;
2628}
2629
2630static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E,
2631 APValue &Value, const FieldDecl *FD) {
2632 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield");
2633
2634 if (!Value.isInt()) {
2635 // Trying to store a pointer-cast-to-integer into a bitfield.
2636 // FIXME: In this case, we should provide the diagnostic for casting
2637 // a pointer to an integer.
2638 assert(Value.isLValue() && "integral value neither int nor lvalue?");
2639 Info.FFDiag(E);
2640 return false;
2641 }
2642
2643 APSInt &Int = Value.getInt();
2644 unsigned OldBitWidth = Int.getBitWidth();
2645 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx);
2646 if (NewBitWidth < OldBitWidth)
2647 Int = Int.trunc(NewBitWidth).extend(OldBitWidth);
2648 return true;
2649}
2650
2651static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E,
2652 llvm::APInt &Res) {
2653 APValue SVal;
2654 if (!Evaluate(SVal, Info, E))
2655 return false;
2656 if (SVal.isInt()) {
2657 Res = SVal.getInt();
2658 return true;
2659 }
2660 if (SVal.isFloat()) {
2661 Res = SVal.getFloat().bitcastToAPInt();
2662 return true;
2663 }
2664 if (SVal.isVector()) {
2665 QualType VecTy = E->getType();
2666 unsigned VecSize = Info.Ctx.getTypeSize(VecTy);
2667 QualType EltTy = VecTy->castAs<VectorType>()->getElementType();
2668 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
2669 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
2670 Res = llvm::APInt::getNullValue(VecSize);
2671 for (unsigned i = 0; i < SVal.getVectorLength(); i++) {
2672 APValue &Elt = SVal.getVectorElt(i);
2673 llvm::APInt EltAsInt;
2674 if (Elt.isInt()) {
2675 EltAsInt = Elt.getInt();
2676 } else if (Elt.isFloat()) {
2677 EltAsInt = Elt.getFloat().bitcastToAPInt();
2678 } else {
2679 // Don't try to handle vectors of anything other than int or float
2680 // (not sure if it's possible to hit this case).
2681 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2682 return false;
2683 }
2684 unsigned BaseEltSize = EltAsInt.getBitWidth();
2685 if (BigEndian)
2686 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize);
2687 else
2688 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize);
2689 }
2690 return true;
2691 }
2692 // Give up if the input isn't an int, float, or vector. For example, we
2693 // reject "(v4i16)(intptr_t)&a".
2694 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
2695 return false;
2696}
2697
2698/// Perform the given integer operation, which is known to need at most BitWidth
2699/// bits, and check for overflow in the original type (if that type was not an
2700/// unsigned type).
2701template<typename Operation>
2702static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E,
2703 const APSInt &LHS, const APSInt &RHS,
2704 unsigned BitWidth, Operation Op,
2705 APSInt &Result) {
2706 if (LHS.isUnsigned()) {
2707 Result = Op(LHS, RHS);
2708 return true;
2709 }
2710
2711 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false);
2712 Result = Value.trunc(LHS.getBitWidth());
2713 if (Result.extend(BitWidth) != Value) {
2714 if (Info.checkingForUndefinedBehavior())
2715 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
2716 diag::warn_integer_constant_overflow)
2717 << Result.toString(10) << E->getType();
2718 else
2719 return HandleOverflow(Info, E, Value, E->getType());
2720 }
2721 return true;
2722}
2723
2724/// Perform the given binary integer operation.
2725static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS,
2726 BinaryOperatorKind Opcode, APSInt RHS,
2727 APSInt &Result) {
2728 switch (Opcode) {
2729 default:
2730 Info.FFDiag(E);
2731 return false;
2732 case BO_Mul:
2733 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2,
2734 std::multiplies<APSInt>(), Result);
2735 case BO_Add:
2736 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2737 std::plus<APSInt>(), Result);
2738 case BO_Sub:
2739 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1,
2740 std::minus<APSInt>(), Result);
2741 case BO_And: Result = LHS & RHS; return true;
2742 case BO_Xor: Result = LHS ^ RHS; return true;
2743 case BO_Or: Result = LHS | RHS; return true;
2744 case BO_Div:
2745 case BO_Rem:
2746 if (RHS == 0) {
2747 Info.FFDiag(E, diag::note_expr_divide_by_zero);
2748 return false;
2749 }
2750 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS);
2751 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports
2752 // this operation and gives the two's complement result.
2753 if (RHS.isNegative() && RHS.isAllOnesValue() &&
2754 LHS.isSigned() && LHS.isMinSignedValue())
2755 return HandleOverflow(Info, E, -LHS.extend(LHS.getBitWidth() + 1),
2756 E->getType());
2757 return true;
2758 case BO_Shl: {
2759 if (Info.getLangOpts().OpenCL)
2760 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2761 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2762 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2763 RHS.isUnsigned());
2764 else if (RHS.isSigned() && RHS.isNegative()) {
2765 // During constant-folding, a negative shift is an opposite shift. Such
2766 // a shift is not a constant expression.
2767 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2768 RHS = -RHS;
2769 goto shift_right;
2770 }
2771 shift_left:
2772 // C++11 [expr.shift]p1: Shift width must be less than the bit width of
2773 // the shifted type.
2774 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2775 if (SA != RHS) {
2776 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2777 << RHS << E->getType() << LHS.getBitWidth();
2778 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) {
2779 // C++11 [expr.shift]p2: A signed left shift must have a non-negative
2780 // operand, and must not overflow the corresponding unsigned type.
2781 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to
2782 // E1 x 2^E2 module 2^N.
2783 if (LHS.isNegative())
2784 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS;
2785 else if (LHS.countLeadingZeros() < SA)
2786 Info.CCEDiag(E, diag::note_constexpr_lshift_discards);
2787 }
2788 Result = LHS << SA;
2789 return true;
2790 }
2791 case BO_Shr: {
2792 if (Info.getLangOpts().OpenCL)
2793 // OpenCL 6.3j: shift values are effectively % word size of LHS.
2794 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(),
2795 static_cast<uint64_t>(LHS.getBitWidth() - 1)),
2796 RHS.isUnsigned());
2797 else if (RHS.isSigned() && RHS.isNegative()) {
2798 // During constant-folding, a negative shift is an opposite shift. Such a
2799 // shift is not a constant expression.
2800 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS;
2801 RHS = -RHS;
2802 goto shift_left;
2803 }
2804 shift_right:
2805 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the
2806 // shifted type.
2807 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1);
2808 if (SA != RHS)
2809 Info.CCEDiag(E, diag::note_constexpr_large_shift)
2810 << RHS << E->getType() << LHS.getBitWidth();
2811 Result = LHS >> SA;
2812 return true;
2813 }
2814
2815 case BO_LT: Result = LHS < RHS; return true;
2816 case BO_GT: Result = LHS > RHS; return true;
2817 case BO_LE: Result = LHS <= RHS; return true;
2818 case BO_GE: Result = LHS >= RHS; return true;
2819 case BO_EQ: Result = LHS == RHS; return true;
2820 case BO_NE: Result = LHS != RHS; return true;
2821 case BO_Cmp:
2822 llvm_unreachable("BO_Cmp should be handled elsewhere");
2823 }
2824}
2825
2826/// Perform the given binary floating-point operation, in-place, on LHS.
2827static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E,
2828 APFloat &LHS, BinaryOperatorKind Opcode,
2829 const APFloat &RHS) {
2830 bool DynamicRM;
2831 llvm::RoundingMode RM = getActiveRoundingMode(Info, E, DynamicRM);
2832 APFloat::opStatus St;
2833 switch (Opcode) {
2834 default:
2835 Info.FFDiag(E);
2836 return false;
2837 case BO_Mul:
2838 St = LHS.multiply(RHS, RM);
2839 break;
2840 case BO_Add:
2841 St = LHS.add(RHS, RM);
2842 break;
2843 case BO_Sub:
2844 St = LHS.subtract(RHS, RM);
2845 break;
2846 case BO_Div:
2847 // [expr.mul]p4:
2848 // If the second operand of / or % is zero the behavior is undefined.
2849 if (RHS.isZero())
2850 Info.CCEDiag(E, diag::note_expr_divide_by_zero);
2851 St = LHS.divide(RHS, RM);
2852 break;
2853 }
2854
2855 // [expr.pre]p4:
2856 // If during the evaluation of an expression, the result is not
2857 // mathematically defined [...], the behavior is undefined.
2858 // FIXME: C++ rules require us to not conform to IEEE 754 here.
2859 if (LHS.isNaN()) {
2860 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN();
2861 return Info.noteUndefinedBehavior();
2862 }
2863
2864 return checkFloatingPointResult(Info, E, St);
2865}
2866
2867static bool handleLogicalOpForVector(const APInt &LHSValue,
2868 BinaryOperatorKind Opcode,
2869 const APInt &RHSValue, APInt &Result) {
2870 bool LHS = (LHSValue != 0);
2871 bool RHS = (RHSValue != 0);
2872
2873 if (Opcode == BO_LAnd)
2874 Result = LHS && RHS;
2875 else
2876 Result = LHS || RHS;
2877 return true;
2878}
2879static bool handleLogicalOpForVector(const APFloat &LHSValue,
2880 BinaryOperatorKind Opcode,
2881 const APFloat &RHSValue, APInt &Result) {
2882 bool LHS = !LHSValue.isZero();
2883 bool RHS = !RHSValue.isZero();
2884
2885 if (Opcode == BO_LAnd)
2886 Result = LHS && RHS;
2887 else
2888 Result = LHS || RHS;
2889 return true;
2890}
2891
2892static bool handleLogicalOpForVector(const APValue &LHSValue,
2893 BinaryOperatorKind Opcode,
2894 const APValue &RHSValue, APInt &Result) {
2895 // The result is always an int type, however operands match the first.
2896 if (LHSValue.getKind() == APValue::Int)
2897 return handleLogicalOpForVector(LHSValue.getInt(), Opcode,
2898 RHSValue.getInt(), Result);
2899 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
2900 return handleLogicalOpForVector(LHSValue.getFloat(), Opcode,
2901 RHSValue.getFloat(), Result);
2902}
2903
2904template <typename APTy>
2905static bool
2906handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode,
2907 const APTy &RHSValue, APInt &Result) {
2908 switch (Opcode) {
2909 default:
2910 llvm_unreachable("unsupported binary operator");
2911 case BO_EQ:
2912 Result = (LHSValue == RHSValue);
2913 break;
2914 case BO_NE:
2915 Result = (LHSValue != RHSValue);
2916 break;
2917 case BO_LT:
2918 Result = (LHSValue < RHSValue);
2919 break;
2920 case BO_GT:
2921 Result = (LHSValue > RHSValue);
2922 break;
2923 case BO_LE:
2924 Result = (LHSValue <= RHSValue);
2925 break;
2926 case BO_GE:
2927 Result = (LHSValue >= RHSValue);
2928 break;
2929 }
2930
2931 return true;
2932}
2933
2934static bool handleCompareOpForVector(const APValue &LHSValue,
2935 BinaryOperatorKind Opcode,
2936 const APValue &RHSValue, APInt &Result) {
2937 // The result is always an int type, however operands match the first.
2938 if (LHSValue.getKind() == APValue::Int)
2939 return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode,
2940 RHSValue.getInt(), Result);
2941 assert(LHSValue.getKind() == APValue::Float && "Should be no other options");
2942 return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode,
2943 RHSValue.getFloat(), Result);
2944}
2945
2946// Perform binary operations for vector types, in place on the LHS.
2947static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E,
2948 BinaryOperatorKind Opcode,
2949 APValue &LHSValue,
2950 const APValue &RHSValue) {
2951 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI &&
2952 "Operation not supported on vector types");
2953
2954 const auto *VT = E->getType()->castAs<VectorType>();
2955 unsigned NumElements = VT->getNumElements();
2956 QualType EltTy = VT->getElementType();
2957
2958 // In the cases (typically C as I've observed) where we aren't evaluating
2959 // constexpr but are checking for cases where the LHS isn't yet evaluatable,
2960 // just give up.
2961 if (!LHSValue.isVector()) {
2962 assert(LHSValue.isLValue() &&
2963 "A vector result that isn't a vector OR uncalculated LValue");
2964 Info.FFDiag(E);
2965 return false;
2966 }
2967
2968 assert(LHSValue.getVectorLength() == NumElements &&
2969 RHSValue.getVectorLength() == NumElements && "Different vector sizes");
2970
2971 SmallVector<APValue, 4> ResultElements;
2972
2973 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) {
2974 APValue LHSElt = LHSValue.getVectorElt(EltNum);
2975 APValue RHSElt = RHSValue.getVectorElt(EltNum);
2976
2977 if (EltTy->isIntegerType()) {
2978 APSInt EltResult{Info.Ctx.getIntWidth(EltTy),
2979 EltTy->isUnsignedIntegerType()};
2980 bool Success = true;
2981
2982 if (BinaryOperator::isLogicalOp(Opcode))
2983 Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2984 else if (BinaryOperator::isComparisonOp(Opcode))
2985 Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult);
2986 else
2987 Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode,
2988 RHSElt.getInt(), EltResult);
2989
2990 if (!Success) {
2991 Info.FFDiag(E);
2992 return false;
2993 }
2994 ResultElements.emplace_back(EltResult);
2995
2996 } else if (EltTy->isFloatingType()) {
2997 assert(LHSElt.getKind() == APValue::Float &&
2998 RHSElt.getKind() == APValue::Float &&
2999 "Mismatched LHS/RHS/Result Type");
3000 APFloat LHSFloat = LHSElt.getFloat();
3001
3002 if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode,
3003 RHSElt.getFloat())) {
3004 Info.FFDiag(E);
3005 return false;
3006 }
3007
3008 ResultElements.emplace_back(LHSFloat);
3009 }
3010 }
3011
3012 LHSValue = APValue(ResultElements.data(), ResultElements.size());
3013 return true;
3014}
3015
3016/// Cast an lvalue referring to a base subobject to a derived class, by
3017/// truncating the lvalue's path to the given length.
3018static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result,
3019 const RecordDecl *TruncatedType,
3020 unsigned TruncatedElements) {
3021 SubobjectDesignator &D = Result.Designator;
3022
3023 // Check we actually point to a derived class object.
3024 if (TruncatedElements == D.Entries.size())
3025 return true;
3026 assert(TruncatedElements >= D.MostDerivedPathLength &&
3027 "not casting to a derived class");
3028 if (!Result.checkSubobject(Info, E, CSK_Derived))
3029 return false;
3030
3031 // Truncate the path to the subobject, and remove any derived-to-base offsets.
3032 const RecordDecl *RD = TruncatedType;
3033 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) {
3034 if (RD->isInvalidDecl()) return false;
3035 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
3036 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]);
3037 if (isVirtualBaseClass(D.Entries[I]))
3038 Result.Offset -= Layout.getVBaseClassOffset(Base);
3039 else
3040 Result.Offset -= Layout.getBaseClassOffset(Base);
3041 RD = Base;
3042 }
3043 D.Entries.resize(TruncatedElements);
3044 return true;
3045}
3046
3047static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3048 const CXXRecordDecl *Derived,
3049 const CXXRecordDecl *Base,
3050 const ASTRecordLayout *RL = nullptr) {
3051 if (!RL) {
3052 if (Derived->isInvalidDecl()) return false;
3053 RL = &Info.Ctx.getASTRecordLayout(Derived);
3054 }
3055
3056 Obj.getLValueOffset() += RL->getBaseClassOffset(Base);
3057 Obj.addDecl(Info, E, Base, /*Virtual*/ false);
3058 return true;
3059}
3060
3061static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj,
3062 const CXXRecordDecl *DerivedDecl,
3063 const CXXBaseSpecifier *Base) {
3064 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl();
3065
3066 if (!Base->isVirtual())
3067 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl);
3068
3069 SubobjectDesignator &D = Obj.Designator;
3070 if (D.Invalid)
3071 return false;
3072
3073 // Extract most-derived object and corresponding type.
3074 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl();
3075 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength))
3076 return false;
3077
3078 // Find the virtual base class.
3079 if (DerivedDecl->isInvalidDecl()) return false;
3080 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl);
3081 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl);
3082 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true);
3083 return true;
3084}
3085
3086static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E,
3087 QualType Type, LValue &Result) {
3088 for (CastExpr::path_const_iterator PathI = E->path_begin(),
3089 PathE = E->path_end();
3090 PathI != PathE; ++PathI) {
3091 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(),
3092 *PathI))
3093 return false;
3094 Type = (*PathI)->getType();
3095 }
3096 return true;
3097}
3098
3099/// Cast an lvalue referring to a derived class to a known base subobject.
3100static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result,
3101 const CXXRecordDecl *DerivedRD,
3102 const CXXRecordDecl *BaseRD) {
3103 CXXBasePaths Paths(/*FindAmbiguities=*/false,
3104 /*RecordPaths=*/true, /*DetectVirtual=*/false);
3105 if (!DerivedRD->isDerivedFrom(BaseRD, Paths))
3106 llvm_unreachable("Class must be derived from the passed in base class!");
3107
3108 for (CXXBasePathElement &Elem : Paths.front())
3109 if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base))
3110 return false;
3111 return true;
3112}
3113
3114/// Update LVal to refer to the given field, which must be a member of the type
3115/// currently described by LVal.
3116static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal,
3117 const FieldDecl *FD,
3118 const ASTRecordLayout *RL = nullptr) {
3119 if (!RL) {
3120 if (FD->getParent()->isInvalidDecl()) return false;
3121 RL = &Info.Ctx.getASTRecordLayout(FD->getParent());
3122 }
3123
3124 unsigned I = FD->getFieldIndex();
3125 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I)));
3126 LVal.addDecl(Info, E, FD);
3127 return true;
3128}
3129
3130/// Update LVal to refer to the given indirect field.
3131static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E,
3132 LValue &LVal,
3133 const IndirectFieldDecl *IFD) {
3134 for (const auto *C : IFD->chain())
3135 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C)))
3136 return false;
3137 return true;
3138}
3139
3140/// Get the size of the given type in char units.
3141static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc,
3142 QualType Type, CharUnits &Size) {
3143 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
3144 // extension.
3145 if (Type->isVoidType() || Type->isFunctionType()) {
3146 Size = CharUnits::One();
3147 return true;
3148 }
3149
3150 if (Type->isDependentType()) {
3151 Info.FFDiag(Loc);
3152 return false;
3153 }
3154
3155 if (!Type->isConstantSizeType()) {
3156 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2.
3157 // FIXME: Better diagnostic.
3158 Info.FFDiag(Loc);
3159 return false;
3160 }
3161
3162 Size = Info.Ctx.getTypeSizeInChars(Type);
3163 return true;
3164}
3165
3166/// Update a pointer value to model pointer arithmetic.
3167/// \param Info - Information about the ongoing evaluation.
3168/// \param E - The expression being evaluated, for diagnostic purposes.
3169/// \param LVal - The pointer value to be updated.
3170/// \param EltTy - The pointee type represented by LVal.
3171/// \param Adjustment - The adjustment, in objects of type EltTy, to add.
3172static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3173 LValue &LVal, QualType EltTy,
3174 APSInt Adjustment) {
3175 CharUnits SizeOfPointee;
3176 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee))
3177 return false;
3178
3179 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee);
3180 return true;
3181}
3182
3183static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E,
3184 LValue &LVal, QualType EltTy,
3185 int64_t Adjustment) {
3186 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy,
3187 APSInt::get(Adjustment));
3188}
3189
3190/// Update an lvalue to refer to a component of a complex number.
3191/// \param Info - Information about the ongoing evaluation.
3192/// \param LVal - The lvalue to be updated.
3193/// \param EltTy - The complex number's component type.
3194/// \param Imag - False for the real component, true for the imaginary.
3195static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
3196 LValue &LVal, QualType EltTy,
3197 bool Imag) {
3198 if (Imag) {
3199 CharUnits SizeOfComponent;
3200 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
3201 return false;
3202 LVal.Offset += SizeOfComponent;
3203 }
3204 LVal.addComplex(Info, E, EltTy, Imag);
3205 return true;
3206}
3207
3208/// Try to evaluate the initializer for a variable declaration.
3209///
3210/// \param Info Information about the ongoing evaluation.
3211/// \param E An expression to be used when printing diagnostics.
3212/// \param VD The variable whose initializer should be obtained.
3213/// \param Version The version of the variable within the frame.
3214/// \param Frame The frame in which the variable was created. Must be null
3215/// if this variable is not local to the evaluation.
3216/// \param Result Filled in with a pointer to the value of the variable.
3217static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
3218 const VarDecl *VD, CallStackFrame *Frame,
3219 unsigned Version, APValue *&Result) {
3220 APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
3221
3222 // If this is a local variable, dig out its value.
3223 if (Frame) {
3224 Result = Frame->getTemporary(VD, Version);
3225 if (Result)
3226 return true;
3227
3228 if (!isa<ParmVarDecl>(VD)) {
3229 // Assume variables referenced within a lambda's call operator that were
3230 // not declared within the call operator are captures and during checking
3231 // of a potential constant expression, assume they are unknown constant
3232 // expressions.
3233 assert(isLambdaCallOperator(Frame->Callee) &&
3234 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) &&
3235 "missing value for local variable");
3236 if (Info.checkingPotentialConstantExpression())
3237 return false;
3238 // FIXME: This diagnostic is bogus; we do support captures. Is this code
3239 // still reachable at all?
3240 Info.FFDiag(E->getBeginLoc(),
3241 diag::note_unimplemented_constexpr_lambda_feature_ast)
3242 << "captures not currently allowed";
3243 return false;
3244 }
3245 }
3246
3247 // If we're currently evaluating the initializer of this declaration, use that
3248 // in-flight value.
3249 if (Info.EvaluatingDecl == Base) {
3250 Result = Info.EvaluatingDeclValue;
3251 return true;
3252 }
3253
3254 if (isa<ParmVarDecl>(VD)) {
3255 // Assume parameters of a potential constant expression are usable in
3256 // constant expressions.
3257 if (!Info.checkingPotentialConstantExpression() ||
3258 !Info.CurrentCall->Callee ||
3259 !Info.CurrentCall->Callee->Equals(VD->getDeclContext())) {
3260 if (Info.getLangOpts().CPlusPlus11) {
3261 Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown)
3262 << VD;
3263 NoteLValueLocation(Info, Base);
3264 } else {
3265 Info.FFDiag(E);
3266 }
3267 }
3268 return false;
3269 }
3270
3271 // Dig out the initializer, and use the declaration which it's attached to.
3272 // FIXME: We should eventually check whether the variable has a reachable
3273 // initializing declaration.
3274 const Expr *Init = VD->getAnyInitializer(VD);
3275 if (!Init) {
3276 // Don't diagnose during potential constant expression checking; an
3277 // initializer might be added later.
3278 if (!Info.checkingPotentialConstantExpression()) {
3279 Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1)
3280 << VD;
3281 NoteLValueLocation(Info, Base);
3282 }
3283 return false;
3284 }
3285
3286 if (Init->isValueDependent()) {
3287 // The DeclRefExpr is not value-dependent, but the variable it refers to
3288 // has a value-dependent initializer. This should only happen in
3289 // constant-folding cases, where the variable is not actually of a suitable
3290 // type for use in a constant expression (otherwise the DeclRefExpr would
3291 // have been value-dependent too), so diagnose that.
3292 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx));
3293 if (!Info.checkingPotentialConstantExpression()) {
3294 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
3295 ? diag::note_constexpr_ltor_non_constexpr
3296 : diag::note_constexpr_ltor_non_integral, 1)
3297 << VD << VD->getType();
3298 NoteLValueLocation(Info, Base);
3299 }
3300 return false;
3301 }
3302
3303 // Check that we can fold the initializer. In C++, we will have already done
3304 // this in the cases where it matters for conformance.
3305 if (!VD->evaluateValue()) {
3306 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3307 NoteLValueLocation(Info, Base);
3308 return false;
3309 }
3310
3311 // Check that the variable is actually usable in constant expressions. For a
3312 // const integral variable or a reference, we might have a non-constant
3313 // initializer that we can nonetheless evaluate the initializer for. Such
3314 // variables are not usable in constant expressions. In C++98, the
3315 // initializer also syntactically needs to be an ICE.
3316 //
3317 // FIXME: We don't diagnose cases that aren't potentially usable in constant
3318 // expressions here; doing so would regress diagnostics for things like
3319 // reading from a volatile constexpr variable.
3320 if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() &&
3321 VD->mightBeUsableInConstantExpressions(Info.Ctx)) ||
3322 ((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) &&
3323 !Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Info.Ctx))) {
3324 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD;
3325 NoteLValueLocation(Info, Base);
3326 }
3327
3328 // Never use the initializer of a weak variable, not even for constant
3329 // folding. We can't be sure that this is the definition that will be used.
3330 if (VD->isWeak()) {
3331 Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD;
3332 NoteLValueLocation(Info, Base);
3333 return false;
3334 }
3335
3336 Result = VD->getEvaluatedValue();
3337 return true;
3338}
3339
3340/// Get the base index of the given base class within an APValue representing
3341/// the given derived class.
3342static unsigned getBaseIndex(const CXXRecordDecl *Derived,
3343 const CXXRecordDecl *Base) {
3344 Base = Base->getCanonicalDecl();
3345 unsigned Index = 0;
3346 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(),
3347 E = Derived->bases_end(); I != E; ++I, ++Index) {
3348 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base)
3349 return Index;
3350 }
3351
3352 llvm_unreachable("base class missing from derived class's bases list");
3353}
3354
3355/// Extract the value of a character from a string literal.
3356static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit,
3357 uint64_t Index) {
3358 assert(!isa<SourceLocExpr>(Lit) &&
3359 "SourceLocExpr should have already been converted to a StringLiteral");
3360
3361 // FIXME: Support MakeStringConstant
3362 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) {
3363 std::string Str;
3364 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str);
3365 assert(Index <= Str.size() && "Index too large");
3366 return APSInt::getUnsigned(Str.c_str()[Index]);
3367 }
3368
3369 if (auto PE = dyn_cast<PredefinedExpr>(Lit))
3370 Lit = PE->getFunctionName();
3371 const StringLiteral *S = cast<StringLiteral>(Lit);
3372 const ConstantArrayType *CAT =
3373 Info.Ctx.getAsConstantArrayType(S->getType());
3374 assert(CAT && "string literal isn't an array");
3375 QualType CharType = CAT->getElementType();
3376 assert(CharType->isIntegerType() && "unexpected character type");
3377
3378 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3379 CharType->isUnsignedIntegerType());
3380 if (Index < S->getLength())
3381 Value = S->getCodeUnit(Index);
3382 return Value;
3383}
3384
3385// Expand a string literal into an array of characters.
3386//
3387// FIXME: This is inefficient; we should probably introduce something similar
3388// to the LLVM ConstantDataArray to make this cheaper.
3389static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S,
3390 APValue &Result,
3391 QualType AllocType = QualType()) {
3392 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
3393 AllocType.isNull() ? S->getType() : AllocType);
3394 assert(CAT && "string literal isn't an array");
3395 QualType CharType = CAT->getElementType();
3396 assert(CharType->isIntegerType() && "unexpected character type");
3397
3398 unsigned Elts = CAT->getSize().getZExtValue();
3399 Result = APValue(APValue::UninitArray(),
3400 std::min(S->getLength(), Elts), Elts);
3401 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(),
3402 CharType->isUnsignedIntegerType());
3403 if (Result.hasArrayFiller())
3404 Result.getArrayFiller() = APValue(Value);
3405 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) {
3406 Value = S->getCodeUnit(I);
3407 Result.getArrayInitializedElt(I) = APValue(Value);
3408 }
3409}
3410
3411// Expand an array so that it has more than Index filled elements.
3412static void expandArray(APValue &Array, unsigned Index) {
3413 unsigned Size = Array.getArraySize();
3414 assert(Index < Size);
3415
3416 // Always at least double the number of elements for which we store a value.
3417 unsigned OldElts = Array.getArrayInitializedElts();
3418 unsigned NewElts = std::max(Index+1, OldElts * 2);
3419 NewElts = std::min(Size, std::max(NewElts, 8u));
3420
3421 // Copy the data across.
3422 APValue NewValue(APValue::UninitArray(), NewElts, Size);
3423 for (unsigned I = 0; I != OldElts; ++I)
3424 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I));
3425 for (unsigned I = OldElts; I != NewElts; ++I)
3426 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller();
3427 if (NewValue.hasArrayFiller())
3428 NewValue.getArrayFiller() = Array.getArrayFiller();
3429 Array.swap(NewValue);
3430}
3431
3432/// Determine whether a type would actually be read by an lvalue-to-rvalue
3433/// conversion. If it's of class type, we may assume that the copy operation
3434/// is trivial. Note that this is never true for a union type with fields
3435/// (because the copy always "reads" the active member) and always true for
3436/// a non-class type.
3437static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD);
3438static bool isReadByLvalueToRvalueConversion(QualType T) {
3439 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3440 return !RD || isReadByLvalueToRvalueConversion(RD);
3441}
3442static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) {
3443 // FIXME: A trivial copy of a union copies the object representation, even if
3444 // the union is empty.
3445 if (RD->isUnion())
3446 return !RD->field_empty();
3447 if (RD->isEmpty())
3448 return false;
3449
3450 for (auto *Field : RD->fields())
3451 if (!Field->isUnnamedBitfield() &&
3452 isReadByLvalueToRvalueConversion(Field->getType()))
3453 return true;
3454
3455 for (auto &BaseSpec : RD->bases())
3456 if (isReadByLvalueToRvalueConversion(BaseSpec.getType()))
3457 return true;
3458
3459 return false;
3460}
3461
3462/// Diagnose an attempt to read from any unreadable field within the specified
3463/// type, which might be a class type.
3464static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK,
3465 QualType T) {
3466 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
3467 if (!RD)
3468 return false;
3469
3470 if (!RD->hasMutableFields())
3471 return false;
3472
3473 for (auto *Field : RD->fields()) {
3474 // If we're actually going to read this field in some way, then it can't
3475 // be mutable. If we're in a union, then assigning to a mutable field
3476 // (even an empty one) can change the active member, so that's not OK.
3477 // FIXME: Add core issue number for the union case.
3478 if (Field->isMutable() &&
3479 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) {
3480 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field;
3481 Info.Note(Field->getLocation(), diag::note_declared_at);
3482 return true;
3483 }
3484
3485 if (diagnoseMutableFields(Info, E, AK, Field->getType()))
3486 return true;
3487 }
3488
3489 for (auto &BaseSpec : RD->bases())
3490 if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType()))
3491 return true;
3492
3493 // All mutable fields were empty, and thus not actually read.
3494 return false;
3495}
3496
3497static bool lifetimeStartedInEvaluation(EvalInfo &Info,
3498 APValue::LValueBase Base,
3499 bool MutableSubobject = false) {
3500 // A temporary or transient heap allocation we created.
3501 if (Base.getCallIndex() || Base.is<DynamicAllocLValue>())
3502 return true;
3503
3504 switch (Info.IsEvaluatingDecl) {
3505 case EvalInfo::EvaluatingDeclKind::None:
3506 return false;
3507
3508 case EvalInfo::EvaluatingDeclKind::Ctor:
3509 // The variable whose initializer we're evaluating.
3510 if (Info.EvaluatingDecl == Base)
3511 return true;
3512
3513 // A temporary lifetime-extended by the variable whose initializer we're
3514 // evaluating.
3515 if (auto *BaseE = Base.dyn_cast<const Expr *>())
3516 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE))
3517 return Info.EvaluatingDecl == BaseMTE->getExtendingDecl();
3518 return false;
3519
3520 case EvalInfo::EvaluatingDeclKind::Dtor:
3521 // C++2a [expr.const]p6:
3522 // [during constant destruction] the lifetime of a and its non-mutable
3523 // subobjects (but not its mutable subobjects) [are] considered to start
3524 // within e.
3525 if (MutableSubobject || Base != Info.EvaluatingDecl)
3526 return false;
3527 // FIXME: We can meaningfully extend this to cover non-const objects, but
3528 // we will need special handling: we should be able to access only
3529 // subobjects of such objects that are themselves declared const.
3530 QualType T = getType(Base);
3531 return T.isConstQualified() || T->isReferenceType();
3532 }
3533
3534 llvm_unreachable("unknown evaluating decl kind");
3535}
3536
3537namespace {
3538/// A handle to a complete object (an object that is not a subobject of
3539/// another object).
3540struct CompleteObject {
3541 /// The identity of the object.
3542 APValue::LValueBase Base;
3543 /// The value of the complete object.
3544 APValue *Value;
3545 /// The type of the complete object.
3546 QualType Type;
3547
3548 CompleteObject() : Value(nullptr) {}
3549 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type)
3550 : Base(Base), Value(Value), Type(Type) {}
3551
3552 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const {
3553 // If this isn't a "real" access (eg, if it's just accessing the type
3554 // info), allow it. We assume the type doesn't change dynamically for
3555 // subobjects of constexpr objects (even though we'd hit UB here if it
3556 // did). FIXME: Is this right?
3557 if (!isAnyAccess(AK))
3558 return true;
3559
3560 // In C++14 onwards, it is permitted to read a mutable member whose
3561 // lifetime began within the evaluation.
3562 // FIXME: Should we also allow this in C++11?
3563 if (!Info.getLangOpts().CPlusPlus14)
3564 return false;
3565 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true);
3566 }
3567
3568 explicit operator bool() const { return !Type.isNull(); }
3569};
3570} // end anonymous namespace
3571
3572static QualType getSubobjectType(QualType ObjType, QualType SubobjType,
3573 bool IsMutable = false) {
3574 // C++ [basic.type.qualifier]p1:
3575 // - A const object is an object of type const T or a non-mutable subobject
3576 // of a const object.
3577 if (ObjType.isConstQualified() && !IsMutable)
3578 SubobjType.addConst();
3579 // - A volatile object is an object of type const T or a subobject of a
3580 // volatile object.
3581 if (ObjType.isVolatileQualified())
3582 SubobjType.addVolatile();
3583 return SubobjType;
3584}
3585
3586/// Find the designated sub-object of an rvalue.
3587template<typename SubobjectHandler>
3588typename SubobjectHandler::result_type
3589findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
3590 const SubobjectDesignator &Sub, SubobjectHandler &handler) {
3591 if (Sub.Invalid)
3592 // A diagnostic will have already been produced.
3593 return handler.failed();
3594 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) {
3595 if (Info.getLangOpts().CPlusPlus11)
3596 Info.FFDiag(E, Sub.isOnePastTheEnd()
3597 ? diag::note_constexpr_access_past_end
3598 : diag::note_constexpr_access_unsized_array)
3599 << handler.AccessKind;
3600 else
3601 Info.FFDiag(E);
3602 return handler.failed();
3603 }
3604
3605 APValue *O = Obj.Value;
3606 QualType ObjType = Obj.Type;
3607 const FieldDecl *LastField = nullptr;
3608 const FieldDecl *VolatileField = nullptr;
3609
3610 // Walk the designator's path to find the subobject.
3611 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
3612 // Reading an indeterminate value is undefined, but assigning over one is OK.
3613 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) ||
3614 (O->isIndeterminate() &&
3615 !isValidIndeterminateAccess(handler.AccessKind))) {
3616 if (!Info.checkingPotentialConstantExpression())
3617 Info.FFDiag(E, diag::note_constexpr_access_uninit)
3618 << handler.AccessKind << O->isIndeterminate();
3619 return handler.failed();
3620 }
3621
3622 // C++ [class.ctor]p5, C++ [class.dtor]p5:
3623 // const and volatile semantics are not applied on an object under
3624 // {con,de}struction.
3625 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) &&
3626 ObjType->isRecordType() &&
3627 Info.isEvaluatingCtorDtor(
3628 Obj.Base, llvm::makeArrayRef(Sub.Entries.begin(),
3629 Sub.Entries.begin() + I)) !=
3630 ConstructionPhase::None) {
3631 ObjType = Info.Ctx.getCanonicalType(ObjType);
3632 ObjType.removeLocalConst();
3633 ObjType.removeLocalVolatile();
3634 }
3635
3636 // If this is our last pass, check that the final object type is OK.
3637 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) {
3638 // Accesses to volatile objects are prohibited.
3639 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) {
3640 if (Info.getLangOpts().CPlusPlus) {
3641 int DiagKind;
3642 SourceLocation Loc;
3643 const NamedDecl *Decl = nullptr;
3644 if (VolatileField) {
3645 DiagKind = 2;
3646 Loc = VolatileField->getLocation();
3647 Decl = VolatileField;
3648 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) {
3649 DiagKind = 1;
3650 Loc = VD->getLocation();
3651 Decl = VD;
3652 } else {
3653 DiagKind = 0;
3654 if (auto *E = Obj.Base.dyn_cast<const Expr *>())
3655 Loc = E->getExprLoc();
3656 }
3657 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1)
3658 << handler.AccessKind << DiagKind << Decl;
3659 Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind;
3660 } else {
3661 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
3662 }
3663 return handler.failed();
3664 }
3665
3666 // If we are reading an object of class type, there may still be more
3667 // things we need to check: if there are any mutable subobjects, we
3668 // cannot perform this read. (This only happens when performing a trivial
3669 // copy or assignment.)
3670 if (ObjType->isRecordType() &&
3671 !Obj.mayAccessMutableMembers(Info, handler.AccessKind) &&
3672 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType))
3673 return handler.failed();
3674 }
3675
3676 if (I == N) {
3677 if (!handler.found(*O, ObjType))
3678 return false;
3679
3680 // If we modified a bit-field, truncate it to the right width.
3681 if (isModification(handler.AccessKind) &&
3682 LastField && LastField->isBitField() &&
3683 !truncateBitfieldValue(Info, E, *O, LastField))
3684 return false;
3685
3686 return true;
3687 }
3688
3689 LastField = nullptr;
3690 if (ObjType->isArrayType()) {
3691 // Next subobject is an array element.
3692 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType);
3693 assert(CAT && "vla in literal type?");
3694 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3695 if (CAT->getSize().ule(Index)) {
3696 // Note, it should not be possible to form a pointer with a valid
3697 // designator which points more than one past the end of the array.
3698 if (Info.getLangOpts().CPlusPlus11)
3699 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3700 << handler.AccessKind;
3701 else
3702 Info.FFDiag(E);
3703 return handler.failed();
3704 }
3705
3706 ObjType = CAT->getElementType();
3707
3708 if (O->getArrayInitializedElts() > Index)
3709 O = &O->getArrayInitializedElt(Index);
3710 else if (!isRead(handler.AccessKind)) {
3711 expandArray(*O, Index);
3712 O = &O->getArrayInitializedElt(Index);
3713 } else
3714 O = &O->getArrayFiller();
3715 } else if (ObjType->isAnyComplexType()) {
3716 // Next subobject is a complex number.
3717 uint64_t Index = Sub.Entries[I].getAsArrayIndex();
3718 if (Index > 1) {
3719 if (Info.getLangOpts().CPlusPlus11)
3720 Info.FFDiag(E, diag::note_constexpr_access_past_end)
3721 << handler.AccessKind;
3722 else
3723 Info.FFDiag(E);
3724 return handler.failed();
3725 }
3726
3727 ObjType = getSubobjectType(
3728 ObjType, ObjType->castAs<ComplexType>()->getElementType());
3729
3730 assert(I == N - 1 && "extracting subobject of scalar?");
3731 if (O->isComplexInt()) {
3732 return handler.found(Index ? O->getComplexIntImag()
3733 : O->getComplexIntReal(), ObjType);
3734 } else {
3735 assert(O->isComplexFloat());
3736 return handler.found(Index ? O->getComplexFloatImag()
3737 : O->getComplexFloatReal(), ObjType);
3738 }
3739 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
3740 if (Field->isMutable() &&
3741 !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) {
3742 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1)
3743 << handler.AccessKind << Field;
3744 Info.Note(Field->getLocation(), diag::note_declared_at);
3745 return handler.failed();
3746 }
3747
3748 // Next subobject is a class, struct or union field.
3749 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl();
3750 if (RD->isUnion()) {
3751 const FieldDecl *UnionField = O->getUnionField();
3752 if (!UnionField ||
3753 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) {
3754 if (I == N - 1 && handler.AccessKind == AK_Construct) {
3755 // Placement new onto an inactive union member makes it active.
3756 O->setUnion(Field, APValue());
3757 } else {
3758 // FIXME: If O->getUnionValue() is absent, report that there's no
3759 // active union member rather than reporting the prior active union
3760 // member. We'll need to fix nullptr_t to not use APValue() as its
3761 // representation first.
3762 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member)
3763 << handler.AccessKind << Field << !UnionField << UnionField;
3764 return handler.failed();
3765 }
3766 }
3767 O = &O->getUnionValue();
3768 } else
3769 O = &O->getStructField(Field->getFieldIndex());
3770
3771 ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable());
3772 LastField = Field;
3773 if (Field->getType().isVolatileQualified())
3774 VolatileField = Field;
3775 } else {
3776 // Next subobject is a base class.
3777 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl();
3778 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]);
3779 O = &O->getStructBase(getBaseIndex(Derived, Base));
3780
3781 ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base));
3782 }
3783 }
3784}
3785
3786namespace {
3787struct ExtractSubobjectHandler {
3788 EvalInfo &Info;
3789 const Expr *E;
3790 APValue &Result;
3791 const AccessKinds AccessKind;
3792
3793 typedef bool result_type;
3794 bool failed() { return false; }
3795 bool found(APValue &Subobj, QualType SubobjType) {
3796 Result = Subobj;
3797 if (AccessKind == AK_ReadObjectRepresentation)
3798 return true;
3799 return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result);
3800 }
3801 bool found(APSInt &Value, QualType SubobjType) {
3802 Result = APValue(Value);
3803 return true;
3804 }
3805 bool found(APFloat &Value, QualType SubobjType) {
3806 Result = APValue(Value);
3807 return true;
3808 }
3809};
3810} // end anonymous namespace
3811
3812/// Extract the designated sub-object of an rvalue.
3813static bool extractSubobject(EvalInfo &Info, const Expr *E,
3814 const CompleteObject &Obj,
3815 const SubobjectDesignator &Sub, APValue &Result,
3816 AccessKinds AK = AK_Read) {
3817 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation);
3818 ExtractSubobjectHandler Handler = {Info, E, Result, AK};
3819 return findSubobject(Info, E, Obj, Sub, Handler);
3820}
3821
3822namespace {
3823struct ModifySubobjectHandler {
3824 EvalInfo &Info;
3825 APValue &NewVal;
3826 const Expr *E;
3827
3828 typedef bool result_type;
3829 static const AccessKinds AccessKind = AK_Assign;
3830
3831 bool checkConst(QualType QT) {
3832 // Assigning to a const object has undefined behavior.
3833 if (QT.isConstQualified()) {
3834 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
3835 return false;
3836 }
3837 return true;
3838 }
3839
3840 bool failed() { return false; }
3841 bool found(APValue &Subobj, QualType SubobjType) {
3842 if (!checkConst(SubobjType))
3843 return false;
3844 // We've been given ownership of NewVal, so just swap it in.
3845 Subobj.swap(NewVal);
3846 return true;
3847 }
3848 bool found(APSInt &Value, QualType SubobjType) {
3849 if (!checkConst(SubobjType))
3850 return false;
3851 if (!NewVal.isInt()) {
3852 // Maybe trying to write a cast pointer value into a complex?
3853 Info.FFDiag(E);
3854 return false;
3855 }
3856 Value = NewVal.getInt();
3857 return true;
3858 }
3859 bool found(APFloat &Value, QualType SubobjType) {
3860 if (!checkConst(SubobjType))
3861 return false;
3862 Value = NewVal.getFloat();
3863 return true;
3864 }
3865};
3866} // end anonymous namespace
3867
3868const AccessKinds ModifySubobjectHandler::AccessKind;
3869
3870/// Update the designated sub-object of an rvalue to the given value.
3871static bool modifySubobject(EvalInfo &Info, const Expr *E,
3872 const CompleteObject &Obj,
3873 const SubobjectDesignator &Sub,
3874 APValue &NewVal) {
3875 ModifySubobjectHandler Handler = { Info, NewVal, E };
3876 return findSubobject(Info, E, Obj, Sub, Handler);
3877}
3878
3879/// Find the position where two subobject designators diverge, or equivalently
3880/// the length of the common initial subsequence.
3881static unsigned FindDesignatorMismatch(QualType ObjType,
3882 const SubobjectDesignator &A,
3883 const SubobjectDesignator &B,
3884 bool &WasArrayIndex) {
3885 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
3886 for (/**/; I != N; ++I) {
3887 if (!ObjType.isNull() &&
3888 (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
3889 // Next subobject is an array element.
3890 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) {
3891 WasArrayIndex = true;
3892 return I;
3893 }
3894 if (ObjType->isAnyComplexType())
3895 ObjType = ObjType->castAs<ComplexType>()->getElementType();
3896 else
3897 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
3898 } else {
3899 if (A.Entries[I].getAsBaseOrMember() !=
3900 B.Entries[I].getAsBaseOrMember()) {
3901 WasArrayIndex = false;
3902 return I;
3903 }
3904 if (const FieldDecl *FD = getAsField(A.Entries[I]))
3905 // Next subobject is a field.
3906 ObjType = FD->getType();
3907 else
3908 // Next subobject is a base class.
3909 ObjType = QualType();
3910 }
3911 }
3912 WasArrayIndex = false;
3913 return I;
3914}
3915
3916/// Determine whether the given subobject designators refer to elements of the
3917/// same array object.
3918static bool AreElementsOfSameArray(QualType ObjType,
3919 const SubobjectDesignator &A,
3920 const SubobjectDesignator &B) {
3921 if (A.Entries.size() != B.Entries.size())
3922 return false;
3923
3924 bool IsArray = A.MostDerivedIsArrayElement;
3925 if (IsArray && A.MostDerivedPathLength != A.Entries.size())
3926 // A is a subobject of the array element.
3927 return false;
3928
3929 // If A (and B) designates an array element, the last entry will be the array
3930 // index. That doesn't have to match. Otherwise, we're in the 'implicit array
3931 // of length 1' case, and the entire path must match.
3932 bool WasArrayIndex;
3933 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex);
3934 return CommonLength >= A.Entries.size() - IsArray;
3935}
3936
3937/// Find the complete object to which an LValue refers.
3938static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
3939 AccessKinds AK, const LValue &LVal,
3940 QualType LValType) {
3941 if (LVal.InvalidBase) {
3942 Info.FFDiag(E);
3943 return CompleteObject();
3944 }
3945
3946 if (!LVal.Base) {
3947 Info.FFDiag(E, diag::note_constexpr_access_null) << AK;
3948 return CompleteObject();
3949 }
3950
3951 CallStackFrame *Frame = nullptr;
3952 unsigned Depth = 0;
3953 if (LVal.getLValueCallIndex()) {
3954 std::tie(Frame, Depth) =
3955 Info.getCallFrameAndDepth(LVal.getLValueCallIndex());
3956 if (!Frame) {
3957 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1)
3958 << AK << LVal.Base.is<const ValueDecl*>();
3959 NoteLValueLocation(Info, LVal.Base);
3960 return CompleteObject();
3961 }
3962 }
3963
3964 bool IsAccess = isAnyAccess(AK);
3965
3966 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type
3967 // is not a constant expression (even if the object is non-volatile). We also
3968 // apply this rule to C++98, in order to conform to the expected 'volatile'
3969 // semantics.
3970 if (isFormalAccess(AK) && LValType.isVolatileQualified()) {
3971 if (Info.getLangOpts().CPlusPlus)
3972 Info.FFDiag(E, diag::note_constexpr_access_volatile_type)
3973 << AK << LValType;
3974 else
3975 Info.FFDiag(E);
3976 return CompleteObject();
3977 }
3978
3979 // Compute value storage location and type of base object.
3980 APValue *BaseVal = nullptr;
3981 QualType BaseType = getType(LVal.Base);
3982
3983 if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl &&
3984 lifetimeStartedInEvaluation(Info, LVal.Base)) {
3985 // This is the object whose initializer we're evaluating, so its lifetime
3986 // started in the current evaluation.
3987 BaseVal = Info.EvaluatingDeclValue;
3988 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) {
3989 // Allow reading from a GUID declaration.
3990 if (auto *GD = dyn_cast<MSGuidDecl>(D)) {
3991 if (isModification(AK)) {
3992 // All the remaining cases do not permit modification of the object.
3993 Info.FFDiag(E, diag::note_constexpr_modify_global);
3994 return CompleteObject();
3995 }
3996 APValue &V = GD->getAsAPValue();
3997 if (V.isAbsent()) {
3998 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
3999 << GD->getType();
4000 return CompleteObject();
4001 }
4002 return CompleteObject(LVal.Base, &V, GD->getType());
4003 }
4004
4005 // Allow reading from template parameter objects.
4006 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D)) {
4007 if (isModification(AK)) {
4008 Info.FFDiag(E, diag::note_constexpr_modify_global);
4009 return CompleteObject();
4010 }
4011 return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()),
4012 TPO->getType());
4013 }
4014
4015 // In C++98, const, non-volatile integers initialized with ICEs are ICEs.
4016 // In C++11, constexpr, non-volatile variables initialized with constant
4017 // expressions are constant expressions too. Inside constexpr functions,
4018 // parameters are constant expressions even if they're non-const.
4019 // In C++1y, objects local to a constant expression (those with a Frame) are
4020 // both readable and writable inside constant expressions.
4021 // In C, such things can also be folded, although they are not ICEs.
4022 const VarDecl *VD = dyn_cast<VarDecl>(D);
4023 if (VD) {
4024 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx))
4025 VD = VDef;
4026 }
4027 if (!VD || VD->isInvalidDecl()) {
4028 Info.FFDiag(E);
4029 return CompleteObject();
4030 }
4031
4032 bool IsConstant = BaseType.isConstant(Info.Ctx);
4033
4034 // Unless we're looking at a local variable or argument in a constexpr call,
4035 // the variable we're reading must be const.
4036 if (!Frame) {
4037 if (IsAccess && isa<ParmVarDecl>(VD)) {
4038 // Access of a parameter that's not associated with a frame isn't going
4039 // to work out, but we can leave it to evaluateVarDeclInit to provide a
4040 // suitable diagnostic.
4041 } else if (Info.getLangOpts().CPlusPlus14 &&
4042 lifetimeStartedInEvaluation(Info, LVal.Base)) {
4043 // OK, we can read and modify an object if we're in the process of
4044 // evaluating its initializer, because its lifetime began in this
4045 // evaluation.
4046 } else if (isModification(AK)) {
4047 // All the remaining cases do not permit modification of the object.
4048 Info.FFDiag(E, diag::note_constexpr_modify_global);
4049 return CompleteObject();
4050 } else if (VD->isConstexpr()) {
4051 // OK, we can read this variable.
4052 } else if (BaseType->isIntegralOrEnumerationType()) {
4053 if (!IsConstant) {
4054 if (!IsAccess)
4055 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4056 if (Info.getLangOpts().CPlusPlus) {
4057 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD;
4058 Info.Note(VD->getLocation(), diag::note_declared_at);
4059 } else {
4060 Info.FFDiag(E);
4061 }
4062 return CompleteObject();
4063 }
4064 } else if (!IsAccess) {
4065 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4066 } else if (IsConstant && Info.checkingPotentialConstantExpression() &&
4067 BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) {
4068 // This variable might end up being constexpr. Don't diagnose it yet.
4069 } else if (IsConstant) {
4070 // Keep evaluating to see what we can do. In particular, we support
4071 // folding of const floating-point types, in order to make static const
4072 // data members of such types (supported as an extension) more useful.
4073 if (Info.getLangOpts().CPlusPlus) {
4074 Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11
4075 ? diag::note_constexpr_ltor_non_constexpr
4076 : diag::note_constexpr_ltor_non_integral, 1)
4077 << VD << BaseType;
4078 Info.Note(VD->getLocation(), diag::note_declared_at);
4079 } else {
4080 Info.CCEDiag(E);
4081 }
4082 } else {
4083 // Never allow reading a non-const value.
4084 if (Info.getLangOpts().CPlusPlus) {
4085 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11
4086 ? diag::note_constexpr_ltor_non_constexpr
4087 : diag::note_constexpr_ltor_non_integral, 1)
4088 << VD << BaseType;
4089 Info.Note(VD->getLocation(), diag::note_declared_at);
4090 } else {
4091 Info.FFDiag(E);
4092 }
4093 return CompleteObject();
4094 }
4095 }
4096
4097 if (!evaluateVarDeclInit(Info, E, VD, Frame, LVal.getLValueVersion(), BaseVal))
4098 return CompleteObject();
4099 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
4100 Optional<DynAlloc*> Alloc = Info.lookupDynamicAlloc(DA);
4101 if (!Alloc) {
4102 Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK;
4103 return CompleteObject();
4104 }
4105 return CompleteObject(LVal.Base, &(*Alloc)->Value,
4106 LVal.Base.getDynamicAllocType());
4107 } else {
4108 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4109
4110 if (!Frame) {
4111 if (const MaterializeTemporaryExpr *MTE =
4112 dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) {
4113 assert(MTE->getStorageDuration() == SD_Static &&
4114 "should have a frame for a non-global materialized temporary");
4115
4116 // C++20 [expr.const]p4: [DR2126]
4117 // An object or reference is usable in constant expressions if it is
4118 // - a temporary object of non-volatile const-qualified literal type
4119 // whose lifetime is extended to that of a variable that is usable
4120 // in constant expressions
4121 //
4122 // C++20 [expr.const]p5:
4123 // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
4124 // - a non-volatile glvalue that refers to an object that is usable
4125 // in constant expressions, or
4126 // - a non-volatile glvalue of literal type that refers to a
4127 // non-volatile object whose lifetime began within the evaluation
4128 // of E;
4129 //
4130 // C++11 misses the 'began within the evaluation of e' check and
4131 // instead allows all temporaries, including things like:
4132 // int &&r = 1;
4133 // int x = ++r;
4134 // constexpr int k = r;
4135 // Therefore we use the C++14-onwards rules in C++11 too.
4136 //
4137 // Note that temporaries whose lifetimes began while evaluating a
4138 // variable's constructor are not usable while evaluating the
4139 // corresponding destructor, not even if they're of const-qualified
4140 // types.
4141 if (!MTE->isUsableInConstantExpressions(Info.Ctx) &&
4142 !lifetimeStartedInEvaluation(Info, LVal.Base)) {
4143 if (!IsAccess)
4144 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4145 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
4146 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
4147 return CompleteObject();
4148 }
4149
4150 BaseVal = MTE->getOrCreateValue(false);
4151 assert(BaseVal && "got reference to unevaluated temporary");
4152 } else {
4153 if (!IsAccess)
4154 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType);
4155 APValue Val;
4156 LVal.moveInto(Val);
4157 Info.FFDiag(E, diag::note_constexpr_access_unreadable_object)
4158 << AK
4159 << Val.getAsString(Info.Ctx,
4160 Info.Ctx.getLValueReferenceType(LValType));
4161 NoteLValueLocation(Info, LVal.Base);
4162 return CompleteObject();
4163 }
4164 } else {
4165 BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion());
4166 assert(BaseVal && "missing value for temporary");
4167 }
4168 }
4169
4170 // In C++14, we can't safely access any mutable state when we might be
4171 // evaluating after an unmodeled side effect. Parameters are modeled as state
4172 // in the caller, but aren't visible once the call returns, so they can be
4173 // modified in a speculatively-evaluated call.
4174 //
4175 // FIXME: Not all local state is mutable. Allow local constant subobjects
4176 // to be read here (but take care with 'mutable' fields).
4177 unsigned VisibleDepth = Depth;
4178 if (llvm::isa_and_nonnull<ParmVarDecl>(
4179 LVal.Base.dyn_cast<const ValueDecl *>()))
4180 ++VisibleDepth;
4181 if ((Frame && Info.getLangOpts().CPlusPlus14 &&
4182 Info.EvalStatus.HasSideEffects) ||
4183 (isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth))
4184 return CompleteObject();
4185
4186 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType);
4187}
4188
4189/// Perform an lvalue-to-rvalue conversion on the given glvalue. This
4190/// can also be used for 'lvalue-to-lvalue' conversions for looking up the
4191/// glvalue referred to by an entity of reference type.
4192///
4193/// \param Info - Information about the ongoing evaluation.
4194/// \param Conv - The expression for which we are performing the conversion.
4195/// Used for diagnostics.
4196/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the
4197/// case of a non-class type).
4198/// \param LVal - The glvalue on which we are attempting to perform this action.
4199/// \param RVal - The produced value will be placed here.
4200/// \param WantObjectRepresentation - If true, we're looking for the object
4201/// representation rather than the value, and in particular,
4202/// there is no requirement that the result be fully initialized.
4203static bool
4204handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type,
4205 const LValue &LVal, APValue &RVal,
4206 bool WantObjectRepresentation = false) {
4207 if (LVal.Designator.Invalid)
4208 return false;
4209
4210 // Check for special cases where there is no existing APValue to look at.
4211 const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
4212
4213 AccessKinds AK =
4214 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read;
4215
4216 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) {
4217 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) {
4218 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
4219 // initializer until now for such expressions. Such an expression can't be
4220 // an ICE in C, so this only matters for fold.
4221 if (Type.isVolatileQualified()) {
4222 Info.FFDiag(Conv);
4223 return false;
4224 }
4225 APValue Lit;
4226 if (!Evaluate(Lit, Info, CLE->getInitializer()))
4227 return false;
4228 CompleteObject LitObj(LVal.Base, &Lit, Base->getType());
4229 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK);
4230 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) {
4231 // Special-case character extraction so we don't have to construct an
4232 // APValue for the whole string.
4233 assert(LVal.Designator.Entries.size() <= 1 &&
4234 "Can only read characters from string literals");
4235 if (LVal.Designator.Entries.empty()) {
4236 // Fail for now for LValue to RValue conversion of an array.
4237 // (This shouldn't show up in C/C++, but it could be triggered by a
4238 // weird EvaluateAsRValue call from a tool.)
4239 Info.FFDiag(Conv);
4240 return false;
4241 }
4242 if (LVal.Designator.isOnePastTheEnd()) {
4243 if (Info.getLangOpts().CPlusPlus11)
4244 Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK;
4245 else
4246 Info.FFDiag(Conv);
4247 return false;
4248 }
4249 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex();
4250 RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex));
4251 return true;
4252 }
4253 }
4254
4255 CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type);
4256 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK);
4257}
4258
4259/// Perform an assignment of Val to LVal. Takes ownership of Val.
4260static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal,
4261 QualType LValType, APValue &Val) {
4262 if (LVal.Designator.Invalid)
4263 return false;
4264
4265 if (!Info.getLangOpts().CPlusPlus14) {
4266 Info.FFDiag(E);
4267 return false;
4268 }
4269
4270 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4271 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val);
4272}
4273
4274namespace {
4275struct CompoundAssignSubobjectHandler {
4276 EvalInfo &Info;
4277 const CompoundAssignOperator *E;
4278 QualType PromotedLHSType;
4279 BinaryOperatorKind Opcode;
4280 const APValue &RHS;
4281
4282 static const AccessKinds AccessKind = AK_Assign;
4283
4284 typedef bool result_type;
4285
4286 bool checkConst(QualType QT) {
4287 // Assigning to a const object has undefined behavior.
4288 if (QT.isConstQualified()) {
4289 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4290 return false;
4291 }
4292 return true;
4293 }
4294
4295 bool failed() { return false; }
4296 bool found(APValue &Subobj, QualType SubobjType) {
4297 switch (Subobj.getKind()) {
4298 case APValue::Int:
4299 return found(Subobj.getInt(), SubobjType);
4300 case APValue::Float:
4301 return found(Subobj.getFloat(), SubobjType);
4302 case APValue::ComplexInt:
4303 case APValue::ComplexFloat:
4304 // FIXME: Implement complex compound assignment.
4305 Info.FFDiag(E);
4306 return false;
4307 case APValue::LValue:
4308 return foundPointer(Subobj, SubobjType);
4309 case APValue::Vector:
4310 return foundVector(Subobj, SubobjType);
4311 default:
4312 // FIXME: can this happen?
4313 Info.FFDiag(E);
4314 return false;
4315 }
4316 }
4317
4318 bool foundVector(APValue &Value, QualType SubobjType) {
4319 if (!checkConst(SubobjType))
4320 return false;
4321
4322 if (!SubobjType->isVectorType()) {
4323 Info.FFDiag(E);
4324 return false;
4325 }
4326 return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS);
4327 }
4328
4329 bool found(APSInt &Value, QualType SubobjType) {
4330 if (!checkConst(SubobjType))
4331 return false;
4332
4333 if (!SubobjType->isIntegerType()) {
4334 // We don't support compound assignment on integer-cast-to-pointer
4335 // values.
4336 Info.FFDiag(E);
4337 return false;
4338 }
4339
4340 if (RHS.isInt()) {
4341 APSInt LHS =
4342 HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value);
4343 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS))
4344 return false;
4345 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS);
4346 return true;
4347 } else if (RHS.isFloat()) {
4348 const FPOptions FPO = E->getFPFeaturesInEffect(
4349 Info.Ctx.getLangOpts());
4350 APFloat FValue(0.0);
4351 return HandleIntToFloatCast(Info, E, FPO, SubobjType, Value,
4352 PromotedLHSType, FValue) &&
4353 handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) &&
4354 HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType,
4355 Value);
4356 }
4357
4358 Info.FFDiag(E);
4359 return false;
4360 }
4361 bool found(APFloat &Value, QualType SubobjType) {
4362 return checkConst(SubobjType) &&
4363 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType,
4364 Value) &&
4365 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) &&
4366 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value);
4367 }
4368 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4369 if (!checkConst(SubobjType))
4370 return false;
4371
4372 QualType PointeeType;
4373 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4374 PointeeType = PT->getPointeeType();
4375
4376 if (PointeeType.isNull() || !RHS.isInt() ||
4377 (Opcode != BO_Add && Opcode != BO_Sub)) {
4378 Info.FFDiag(E);
4379 return false;
4380 }
4381
4382 APSInt Offset = RHS.getInt();
4383 if (Opcode == BO_Sub)
4384 negateAsSigned(Offset);
4385
4386 LValue LVal;
4387 LVal.setFrom(Info.Ctx, Subobj);
4388 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset))
4389 return false;
4390 LVal.moveInto(Subobj);
4391 return true;
4392 }
4393};
4394} // end anonymous namespace
4395
4396const AccessKinds CompoundAssignSubobjectHandler::AccessKind;
4397
4398/// Perform a compound assignment of LVal <op>= RVal.
4399static bool handleCompoundAssignment(EvalInfo &Info,
4400 const CompoundAssignOperator *E,
4401 const LValue &LVal, QualType LValType,
4402 QualType PromotedLValType,
4403 BinaryOperatorKind Opcode,
4404 const APValue &RVal) {
4405 if (LVal.Designator.Invalid)
4406 return false;
4407
4408 if (!Info.getLangOpts().CPlusPlus14) {
4409 Info.FFDiag(E);
4410 return false;
4411 }
4412
4413 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType);
4414 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode,
4415 RVal };
4416 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4417}
4418
4419namespace {
4420struct IncDecSubobjectHandler {
4421 EvalInfo &Info;
4422 const UnaryOperator *E;
4423 AccessKinds AccessKind;
4424 APValue *Old;
4425
4426 typedef bool result_type;
4427
4428 bool checkConst(QualType QT) {
4429 // Assigning to a const object has undefined behavior.
4430 if (QT.isConstQualified()) {
4431 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT;
4432 return false;
4433 }
4434 return true;
4435 }
4436
4437 bool failed() { return false; }
4438 bool found(APValue &Subobj, QualType SubobjType) {
4439 // Stash the old value. Also clear Old, so we don't clobber it later
4440 // if we're post-incrementing a complex.
4441 if (Old) {
4442 *Old = Subobj;
4443 Old = nullptr;
4444 }
4445
4446 switch (Subobj.getKind()) {
4447 case APValue::Int:
4448 return found(Subobj.getInt(), SubobjType);
4449 case APValue::Float:
4450 return found(Subobj.getFloat(), SubobjType);
4451 case APValue::ComplexInt:
4452 return found(Subobj.getComplexIntReal(),
4453 SubobjType->castAs<ComplexType>()->getElementType()
4454 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4455 case APValue::ComplexFloat:
4456 return found(Subobj.getComplexFloatReal(),
4457 SubobjType->castAs<ComplexType>()->getElementType()
4458 .withCVRQualifiers(SubobjType.getCVRQualifiers()));
4459 case APValue::LValue:
4460 return foundPointer(Subobj, SubobjType);
4461 default:
4462 // FIXME: can this happen?
4463 Info.FFDiag(E);
4464 return false;
4465 }
4466 }
4467 bool found(APSInt &Value, QualType SubobjType) {
4468 if (!checkConst(SubobjType))
4469 return false;
4470
4471 if (!SubobjType->isIntegerType()) {
4472 // We don't support increment / decrement on integer-cast-to-pointer
4473 // values.
4474 Info.FFDiag(E);
4475 return false;
4476 }
4477
4478 if (Old) *Old = APValue(Value);
4479
4480 // bool arithmetic promotes to int, and the conversion back to bool
4481 // doesn't reduce mod 2^n, so special-case it.
4482 if (SubobjType->isBooleanType()) {
4483 if (AccessKind == AK_Increment)
4484 Value = 1;
4485 else
4486 Value = !Value;
4487 return true;
4488 }
4489
4490 bool WasNegative = Value.isNegative();
4491 if (AccessKind == AK_Increment) {
4492 ++Value;
4493
4494 if (!WasNegative && Value.isNegative() && E->canOverflow()) {
4495 APSInt ActualValue(Value, /*IsUnsigned*/true);
4496 return HandleOverflow(Info, E, ActualValue, SubobjType);
4497 }
4498 } else {
4499 --Value;
4500
4501 if (WasNegative && !Value.isNegative() && E->canOverflow()) {
4502 unsigned BitWidth = Value.getBitWidth();
4503 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false);
4504 ActualValue.setBit(BitWidth);
4505 return HandleOverflow(Info, E, ActualValue, SubobjType);
4506 }
4507 }
4508 return true;
4509 }
4510 bool found(APFloat &Value, QualType SubobjType) {
4511 if (!checkConst(SubobjType))
4512 return false;
4513
4514 if (Old) *Old = APValue(Value);
4515
4516 APFloat One(Value.getSemantics(), 1);
4517 if (AccessKind == AK_Increment)
4518 Value.add(One, APFloat::rmNearestTiesToEven);
4519 else
4520 Value.subtract(One, APFloat::rmNearestTiesToEven);
4521 return true;
4522 }
4523 bool foundPointer(APValue &Subobj, QualType SubobjType) {
4524 if (!checkConst(SubobjType))
4525 return false;
4526
4527 QualType PointeeType;
4528 if (const PointerType *PT = SubobjType->getAs<PointerType>())
4529 PointeeType = PT->getPointeeType();
4530 else {
4531 Info.FFDiag(E);
4532 return false;
4533 }
4534
4535 LValue LVal;
4536 LVal.setFrom(Info.Ctx, Subobj);
4537 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType,
4538 AccessKind == AK_Increment ? 1 : -1))
4539 return false;
4540 LVal.moveInto(Subobj);
4541 return true;
4542 }
4543};
4544} // end anonymous namespace
4545
4546/// Perform an increment or decrement on LVal.
4547static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal,
4548 QualType LValType, bool IsIncrement, APValue *Old) {
4549 if (LVal.Designator.Invalid)
4550 return false;
4551
4552 if (!Info.getLangOpts().CPlusPlus14) {
4553 Info.FFDiag(E);
4554 return false;
4555 }
4556
4557 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement;
4558 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType);
4559 IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old};
4560 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler);
4561}
4562
4563/// Build an lvalue for the object argument of a member function call.
4564static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object,
4565 LValue &This) {
4566 if (Object->getType()->isPointerType() && Object->isRValue())
4567 return EvaluatePointer(Object, This, Info);
4568
4569 if (Object->isGLValue())
4570 return EvaluateLValue(Object, This, Info);
4571
4572 if (Object->getType()->isLiteralType(Info.Ctx))
4573 return EvaluateTemporary(Object, This, Info);
4574
4575 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType();
4576 return false;
4577}
4578
4579/// HandleMemberPointerAccess - Evaluate a member access operation and build an
4580/// lvalue referring to the result.
4581///
4582/// \param Info - Information about the ongoing evaluation.
4583/// \param LV - An lvalue referring to the base of the member pointer.
4584/// \param RHS - The member pointer expression.
4585/// \param IncludeMember - Specifies whether the member itself is included in
4586/// the resulting LValue subobject designator. This is not possible when
4587/// creating a bound member function.
4588/// \return The field or method declaration to which the member pointer refers,
4589/// or 0 if evaluation fails.
4590static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4591 QualType LVType,
4592 LValue &LV,
4593 const Expr *RHS,
4594 bool IncludeMember = true) {
4595 MemberPtr MemPtr;
4596 if (!EvaluateMemberPointer(RHS, MemPtr, Info))
4597 return nullptr;
4598
4599 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to
4600 // member value, the behavior is undefined.
4601 if (!MemPtr.getDecl()) {
4602 // FIXME: Specific diagnostic.
4603 Info.FFDiag(RHS);
4604 return nullptr;
4605 }
4606
4607 if (MemPtr.isDerivedMember()) {
4608 // This is a member of some derived class. Truncate LV appropriately.
4609 // The end of the derived-to-base path for the base object must match the
4610 // derived-to-base path for the member pointer.
4611 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() >
4612 LV.Designator.Entries.size()) {
4613 Info.FFDiag(RHS);
4614 return nullptr;
4615 }
4616 unsigned PathLengthToMember =
4617 LV.Designator.Entries.size() - MemPtr.Path.size();
4618 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) {
4619 const CXXRecordDecl *LVDecl = getAsBaseClass(
4620 LV.Designator.Entries[PathLengthToMember + I]);
4621 const CXXRecordDecl *MPDecl = MemPtr.Path[I];
4622 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) {
4623 Info.FFDiag(RHS);
4624 return nullptr;
4625 }
4626 }
4627
4628 // Truncate the lvalue to the appropriate derived class.
4629 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(),
4630 PathLengthToMember))
4631 return nullptr;
4632 } else if (!MemPtr.Path.empty()) {
4633 // Extend the LValue path with the member pointer's path.
4634 LV.Designator.Entries.reserve(LV.Designator.Entries.size() +
4635 MemPtr.Path.size() + IncludeMember);
4636
4637 // Walk down to the appropriate base class.
4638 if (const PointerType *PT = LVType->getAs<PointerType>())
4639 LVType = PT->getPointeeType();
4640 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl();
4641 assert(RD && "member pointer access on non-class-type expression");
4642 // The first class in the path is that of the lvalue.
4643 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) {
4644 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1];
4645 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base))
4646 return nullptr;
4647 RD = Base;
4648 }
4649 // Finally cast to the class containing the member.
4650 if (!HandleLValueDirectBase(Info, RHS, LV, RD,
4651 MemPtr.getContainingRecord()))
4652 return nullptr;
4653 }
4654
4655 // Add the member. Note that we cannot build bound member functions here.
4656 if (IncludeMember) {
4657 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) {
4658 if (!HandleLValueMember(Info, RHS, LV, FD))
4659 return nullptr;
4660 } else if (const IndirectFieldDecl *IFD =
4661 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) {
4662 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD))
4663 return nullptr;
4664 } else {
4665 llvm_unreachable("can't construct reference to bound member function");
4666 }
4667 }
4668
4669 return MemPtr.getDecl();
4670}
4671
4672static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info,
4673 const BinaryOperator *BO,
4674 LValue &LV,
4675 bool IncludeMember = true) {
4676 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI);
4677
4678 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) {
4679 if (Info.noteFailure()) {
4680 MemberPtr MemPtr;
4681 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info);
4682 }
4683 return nullptr;
4684 }
4685
4686 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV,
4687 BO->getRHS(), IncludeMember);
4688}
4689
4690/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on
4691/// the provided lvalue, which currently refers to the base object.
4692static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E,
4693 LValue &Result) {
4694 SubobjectDesignator &D = Result.Designator;
4695 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived))
4696 return false;
4697
4698 QualType TargetQT = E->getType();
4699 if (const PointerType *PT = TargetQT->getAs<PointerType>())
4700 TargetQT = PT->getPointeeType();
4701
4702 // Check this cast lands within the final derived-to-base subobject path.
4703 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) {
4704 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4705 << D.MostDerivedType << TargetQT;
4706 return false;
4707 }
4708
4709 // Check the type of the final cast. We don't need to check the path,
4710 // since a cast can only be formed if the path is unique.
4711 unsigned NewEntriesSize = D.Entries.size() - E->path_size();
4712 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl();
4713 const CXXRecordDecl *FinalType;
4714 if (NewEntriesSize == D.MostDerivedPathLength)
4715 FinalType = D.MostDerivedType->getAsCXXRecordDecl();
4716 else
4717 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]);
4718 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) {
4719 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast)
4720 << D.MostDerivedType << TargetQT;
4721 return false;
4722 }
4723
4724 // Truncate the lvalue to the appropriate derived class.
4725 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize);
4726}
4727
4728/// Get the value to use for a default-initialized object of type T.
4729/// Return false if it encounters something invalid.
4730static bool getDefaultInitValue(QualType T, APValue &Result) {
4731 bool Success = true;
4732 if (auto *RD = T->getAsCXXRecordDecl()) {
4733 if (RD->isInvalidDecl()) {
4734 Result = APValue();
4735 return false;
4736 }
4737 if (RD->isUnion()) {
4738 Result = APValue((const FieldDecl *)nullptr);
4739 return true;
4740 }
4741 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
4742 std::distance(RD->field_begin(), RD->field_end()));
4743
4744 unsigned Index = 0;
4745 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
4746 End = RD->bases_end();
4747 I != End; ++I, ++Index)
4748 Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index));
4749
4750 for (const auto *I : RD->fields()) {
4751 if (I->isUnnamedBitfield())
4752 continue;
4753 Success &= getDefaultInitValue(I->getType(),
4754 Result.getStructField(I->getFieldIndex()));
4755 }
4756 return Success;
4757 }
4758
4759 if (auto *AT =
4760 dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) {
4761 Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue());
4762 if (Result.hasArrayFiller())
4763 Success &=
4764 getDefaultInitValue(AT->getElementType(), Result.getArrayFiller());
4765
4766 return Success;
4767 }
4768
4769 Result = APValue::IndeterminateValue();
4770 return true;
4771}
4772
4773namespace {
4774enum EvalStmtResult {
4775 /// Evaluation failed.
4776 ESR_Failed,
4777 /// Hit a 'return' statement.
4778 ESR_Returned,
4779 /// Evaluation succeeded.
4780 ESR_Succeeded,
4781 /// Hit a 'continue' statement.
4782 ESR_Continue,
4783 /// Hit a 'break' statement.
4784 ESR_Break,
4785 /// Still scanning for 'case' or 'default' statement.
4786 ESR_CaseNotFound
4787};
4788}
4789
4790static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) {
4791 // We don't need to evaluate the initializer for a static local.
4792 if (!VD->hasLocalStorage())
4793 return true;
4794
4795 LValue Result;
4796 APValue &Val = Info.CurrentCall->createTemporary(VD, VD->getType(),
4797 ScopeKind::Block, Result);
4798
4799 const Expr *InitE = VD->getInit();
4800 if (!InitE) {
4801 if (VD->getType()->isDependentType())
4802 return Info.noteSideEffect();
4803 return getDefaultInitValue(VD->getType(), Val);
4804 }
4805 if (InitE->isValueDependent())
4806 return false;
4807
4808 if (!EvaluateInPlace(Val, Info, Result, InitE)) {
4809 // Wipe out any partially-computed value, to allow tracking that this
4810 // evaluation failed.
4811 Val = APValue();
4812 return false;
4813 }
4814
4815 return true;
4816}
4817
4818static bool EvaluateDecl(EvalInfo &Info, const Decl *D) {
4819 bool OK = true;
4820
4821 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
4822 OK &= EvaluateVarDecl(Info, VD);
4823
4824 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D))
4825 for (auto *BD : DD->bindings())
4826 if (auto *VD = BD->getHoldingVar())
4827 OK &= EvaluateDecl(Info, VD);
4828
4829 return OK;
4830}
4831
4832static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) {
4833 assert(E->isValueDependent());
4834 if (Info.noteSideEffect())
4835 return true;
4836 assert(E->containsErrors() && "valid value-dependent expression should never "
4837 "reach invalid code path.");
4838 return false;
4839}
4840
4841/// Evaluate a condition (either a variable declaration or an expression).
4842static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl,
4843 const Expr *Cond, bool &Result) {
4844 if (Cond->isValueDependent())
4845 return false;
4846 FullExpressionRAII Scope(Info);
4847 if (CondDecl && !EvaluateDecl(Info, CondDecl))
4848 return false;
4849 if (!EvaluateAsBooleanCondition(Cond, Result, Info))
4850 return false;
4851 return Scope.destroy();
4852}
4853
4854namespace {
4855/// A location where the result (returned value) of evaluating a
4856/// statement should be stored.
4857struct StmtResult {
4858 /// The APValue that should be filled in with the returned value.
4859 APValue &Value;
4860 /// The location containing the result, if any (used to support RVO).
4861 const LValue *Slot;
4862};
4863
4864struct TempVersionRAII {
4865 CallStackFrame &Frame;
4866
4867 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) {
4868 Frame.pushTempVersion();
4869 }
4870
4871 ~TempVersionRAII() {
4872 Frame.popTempVersion();
4873 }
4874};
4875
4876}
4877
4878static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4879 const Stmt *S,
4880 const SwitchCase *SC = nullptr);
4881
4882/// Evaluate the body of a loop, and translate the result as appropriate.
4883static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info,
4884 const Stmt *Body,
4885 const SwitchCase *Case = nullptr) {
4886 BlockScopeRAII Scope(Info);
4887
4888 EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case);
4889 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4890 ESR = ESR_Failed;
4891
4892 switch (ESR) {
4893 case ESR_Break:
4894 return ESR_Succeeded;
4895 case ESR_Succeeded:
4896 case ESR_Continue:
4897 return ESR_Continue;
4898 case ESR_Failed:
4899 case ESR_Returned:
4900 case ESR_CaseNotFound:
4901 return ESR;
4902 }
4903 llvm_unreachable("Invalid EvalStmtResult!");
4904}
4905
4906/// Evaluate a switch statement.
4907static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info,
4908 const SwitchStmt *SS) {
4909 BlockScopeRAII Scope(Info);
4910
4911 // Evaluate the switch condition.
4912 APSInt Value;
4913 {
4914 if (const Stmt *Init = SS->getInit()) {
4915 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
4916 if (ESR != ESR_Succeeded) {
4917 if (ESR != ESR_Failed && !Scope.destroy())
4918 ESR = ESR_Failed;
4919 return ESR;
4920 }
4921 }
4922
4923 FullExpressionRAII CondScope(Info);
4924 if (SS->getConditionVariable() &&
4925 !EvaluateDecl(Info, SS->getConditionVariable()))
4926 return ESR_Failed;
4927 if (!EvaluateInteger(SS->getCond(), Value, Info))
4928 return ESR_Failed;
4929 if (!CondScope.destroy())
4930 return ESR_Failed;
4931 }
4932
4933 // Find the switch case corresponding to the value of the condition.
4934 // FIXME: Cache this lookup.
4935 const SwitchCase *Found = nullptr;
4936 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC;
4937 SC = SC->getNextSwitchCase()) {
4938 if (isa<DefaultStmt>(SC)) {
4939 Found = SC;
4940 continue;
4941 }
4942
4943 const CaseStmt *CS = cast<CaseStmt>(SC);
4944 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx);
4945 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx)
4946 : LHS;
4947 if (LHS <= Value && Value <= RHS) {
4948 Found = SC;
4949 break;
4950 }
4951 }
4952
4953 if (!Found)
4954 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
4955
4956 // Search the switch body for the switch case and evaluate it from there.
4957 EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found);
4958 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy())
4959 return ESR_Failed;
4960
4961 switch (ESR) {
4962 case ESR_Break:
4963 return ESR_Succeeded;
4964 case ESR_Succeeded:
4965 case ESR_Continue:
4966 case ESR_Failed:
4967 case ESR_Returned:
4968 return ESR;
4969 case ESR_CaseNotFound:
4970 // This can only happen if the switch case is nested within a statement
4971 // expression. We have no intention of supporting that.
4972 Info.FFDiag(Found->getBeginLoc(),
4973 diag::note_constexpr_stmt_expr_unsupported);
4974 return ESR_Failed;
4975 }
4976 llvm_unreachable("Invalid EvalStmtResult!");
4977}
4978
4979// Evaluate a statement.
4980static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info,
4981 const Stmt *S, const SwitchCase *Case) {
4982 if (!Info.nextStep(S))
4983 return ESR_Failed;
4984
4985 // If we're hunting down a 'case' or 'default' label, recurse through
4986 // substatements until we hit the label.
4987 if (Case) {
4988 switch (S->getStmtClass()) {
4989 case Stmt::CompoundStmtClass:
4990 // FIXME: Precompute which substatement of a compound statement we
4991 // would jump to, and go straight there rather than performing a
4992 // linear scan each time.
4993 case Stmt::LabelStmtClass:
4994 case Stmt::AttributedStmtClass:
4995 case Stmt::DoStmtClass:
4996 break;
4997
4998 case Stmt::CaseStmtClass:
4999 case Stmt::DefaultStmtClass:
5000 if (Case == S)
5001 Case = nullptr;
5002 break;
5003
5004 case Stmt::IfStmtClass: {
5005 // FIXME: Precompute which side of an 'if' we would jump to, and go
5006 // straight there rather than scanning both sides.
5007 const IfStmt *IS = cast<IfStmt>(S);
5008
5009 // Wrap the evaluation in a block scope, in case it's a DeclStmt
5010 // preceded by our switch label.
5011 BlockScopeRAII Scope(Info);
5012
5013 // Step into the init statement in case it brings an (uninitialized)
5014 // variable into scope.
5015 if (const Stmt *Init = IS->getInit()) {
5016 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
5017 if (ESR != ESR_CaseNotFound) {
5018 assert(ESR != ESR_Succeeded);
5019 return ESR;
5020 }
5021 }
5022
5023 // Condition variable must be initialized if it exists.
5024 // FIXME: We can skip evaluating the body if there's a condition
5025 // variable, as there can't be any case labels within it.
5026 // (The same is true for 'for' statements.)
5027
5028 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case);
5029 if (ESR == ESR_Failed)
5030 return ESR;
5031 if (ESR != ESR_CaseNotFound)
5032 return Scope.destroy() ? ESR : ESR_Failed;
5033 if (!IS->getElse())
5034 return ESR_CaseNotFound;
5035
5036 ESR = EvaluateStmt(Result, Info, IS->getElse(), Case);
5037 if (ESR == ESR_Failed)
5038 return ESR;
5039 if (ESR != ESR_CaseNotFound)
5040 return Scope.destroy() ? ESR : ESR_Failed;
5041 return ESR_CaseNotFound;
5042 }
5043
5044 case Stmt::WhileStmtClass: {
5045 EvalStmtResult ESR =
5046 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case);
5047 if (ESR != ESR_Continue)
5048 return ESR;
5049 break;
5050 }
5051
5052 case Stmt::ForStmtClass: {
5053 const ForStmt *FS = cast<ForStmt>(S);
5054 BlockScopeRAII Scope(Info);
5055
5056 // Step into the init statement in case it brings an (uninitialized)
5057 // variable into scope.
5058 if (const Stmt *Init = FS->getInit()) {
5059 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case);
5060 if (ESR != ESR_CaseNotFound) {
5061 assert(ESR != ESR_Succeeded);
5062 return ESR;
5063 }
5064 }
5065
5066 EvalStmtResult ESR =
5067 EvaluateLoopBody(Result, Info, FS->getBody(), Case);
5068 if (ESR != ESR_Continue)
5069 return ESR;
5070 if (const auto *Inc = FS->getInc()) {
5071 if (Inc->isValueDependent()) {
5072 if (!EvaluateDependentExpr(Inc, Info))
5073 return ESR_Failed;
5074 } else {
5075 FullExpressionRAII IncScope(Info);
5076 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
5077 return ESR_Failed;
5078 }
5079 }
5080 break;
5081 }
5082
5083 case Stmt::DeclStmtClass: {
5084 // Start the lifetime of any uninitialized variables we encounter. They
5085 // might be used by the selected branch of the switch.
5086 const DeclStmt *DS = cast<DeclStmt>(S);
5087 for (const auto *D : DS->decls()) {
5088 if (const auto *VD = dyn_cast<VarDecl>(D)) {
5089 if (VD->hasLocalStorage() && !VD->getInit())
5090 if (!EvaluateVarDecl(Info, VD))
5091 return ESR_Failed;
5092 // FIXME: If the variable has initialization that can't be jumped
5093 // over, bail out of any immediately-surrounding compound-statement
5094 // too. There can't be any case labels here.
5095 }
5096 }
5097 return ESR_CaseNotFound;
5098 }
5099
5100 default:
5101 return ESR_CaseNotFound;
5102 }
5103 }
5104
5105 switch (S->getStmtClass()) {
5106 default:
5107 if (const Expr *E = dyn_cast<Expr>(S)) {
5108 if (E->isValueDependent()) {
5109 if (!EvaluateDependentExpr(E, Info))
5110 return ESR_Failed;
5111 } else {
5112 // Don't bother evaluating beyond an expression-statement which couldn't
5113 // be evaluated.
5114 // FIXME: Do we need the FullExpressionRAII object here?
5115 // VisitExprWithCleanups should create one when necessary.
5116 FullExpressionRAII Scope(Info);
5117 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy())
5118 return ESR_Failed;
5119 }
5120 return ESR_Succeeded;
5121 }
5122
5123 Info.FFDiag(S->getBeginLoc());
5124 return ESR_Failed;
5125
5126 case Stmt::NullStmtClass:
5127 return ESR_Succeeded;
5128
5129 case Stmt::DeclStmtClass: {
5130 const DeclStmt *DS = cast<DeclStmt>(S);
5131 for (const auto *D : DS->decls()) {
5132 // Each declaration initialization is its own full-expression.
5133 FullExpressionRAII Scope(Info);
5134 if (!EvaluateDecl(Info, D) && !Info.noteFailure())
5135 return ESR_Failed;
5136 if (!Scope.destroy())
5137 return ESR_Failed;
5138 }
5139 return ESR_Succeeded;
5140 }
5141
5142 case Stmt::ReturnStmtClass: {
5143 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue();
5144 FullExpressionRAII Scope(Info);
5145 if (RetExpr && RetExpr->isValueDependent()) {
5146 EvaluateDependentExpr(RetExpr, Info);
5147 // We know we returned, but we don't know what the value is.
5148 return ESR_Failed;
5149 }
5150 if (RetExpr &&
5151 !(Result.Slot
5152 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr)
5153 : Evaluate(Result.Value, Info, RetExpr)))
5154 return ESR_Failed;
5155 return Scope.destroy() ? ESR_Returned : ESR_Failed;
5156 }
5157
5158 case Stmt::CompoundStmtClass: {
5159 BlockScopeRAII Scope(Info);
5160
5161 const CompoundStmt *CS = cast<CompoundStmt>(S);
5162 for (const auto *BI : CS->body()) {
5163 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case);
5164 if (ESR == ESR_Succeeded)
5165 Case = nullptr;
5166 else if (ESR != ESR_CaseNotFound) {
5167 if (ESR != ESR_Failed && !Scope.destroy())
5168 return ESR_Failed;
5169 return ESR;
5170 }
5171 }
5172 if (Case)
5173 return ESR_CaseNotFound;
5174 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5175 }
5176
5177 case Stmt::IfStmtClass: {
5178 const IfStmt *IS = cast<IfStmt>(S);
5179
5180 // Evaluate the condition, as either a var decl or as an expression.
5181 BlockScopeRAII Scope(Info);
5182 if (const Stmt *Init = IS->getInit()) {
5183 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init);
5184 if (ESR != ESR_Succeeded) {
5185 if (ESR != ESR_Failed && !Scope.destroy())
5186 return ESR_Failed;
5187 return ESR;
5188 }
5189 }
5190 bool Cond;
5191 if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), Cond))
5192 return ESR_Failed;
5193
5194 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) {
5195 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt);
5196 if (ESR != ESR_Succeeded) {
5197 if (ESR != ESR_Failed && !Scope.destroy())
5198 return ESR_Failed;
5199 return ESR;
5200 }
5201 }
5202 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5203 }
5204
5205 case Stmt::WhileStmtClass: {
5206 const WhileStmt *WS = cast<WhileStmt>(S);
5207 while (true) {
5208 BlockScopeRAII Scope(Info);
5209 bool Continue;
5210 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(),
5211 Continue))
5212 return ESR_Failed;
5213 if (!Continue)
5214 break;
5215
5216 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody());
5217 if (ESR != ESR_Continue) {
5218 if (ESR != ESR_Failed && !Scope.destroy())
5219 return ESR_Failed;
5220 return ESR;
5221 }
5222 if (!Scope.destroy())
5223 return ESR_Failed;
5224 }
5225 return ESR_Succeeded;
5226 }
5227
5228 case Stmt::DoStmtClass: {
5229 const DoStmt *DS = cast<DoStmt>(S);
5230 bool Continue;
5231 do {
5232 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case);
5233 if (ESR != ESR_Continue)
5234 return ESR;
5235 Case = nullptr;
5236
5237 if (DS->getCond()->isValueDependent()) {
5238 EvaluateDependentExpr(DS->getCond(), Info);
5239 // Bailout as we don't know whether to keep going or terminate the loop.
5240 return ESR_Failed;
5241 }
5242 FullExpressionRAII CondScope(Info);
5243 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) ||
5244 !CondScope.destroy())
5245 return ESR_Failed;
5246 } while (Continue);
5247 return ESR_Succeeded;
5248 }
5249
5250 case Stmt::ForStmtClass: {
5251 const ForStmt *FS = cast<ForStmt>(S);
5252 BlockScopeRAII ForScope(Info);
5253 if (FS->getInit()) {
5254 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5255 if (ESR != ESR_Succeeded) {
5256 if (ESR != ESR_Failed && !ForScope.destroy())
5257 return ESR_Failed;
5258 return ESR;
5259 }
5260 }
5261 while (true) {
5262 BlockScopeRAII IterScope(Info);
5263 bool Continue = true;
5264 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(),
5265 FS->getCond(), Continue))
5266 return ESR_Failed;
5267 if (!Continue)
5268 break;
5269
5270 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5271 if (ESR != ESR_Continue) {
5272 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy()))
5273 return ESR_Failed;
5274 return ESR;
5275 }
5276
5277 if (const auto *Inc = FS->getInc()) {
5278 if (Inc->isValueDependent()) {
5279 if (!EvaluateDependentExpr(Inc, Info))
5280 return ESR_Failed;
5281 } else {
5282 FullExpressionRAII IncScope(Info);
5283 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy())
5284 return ESR_Failed;
5285 }
5286 }
5287
5288 if (!IterScope.destroy())
5289 return ESR_Failed;
5290 }
5291 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed;
5292 }
5293
5294 case Stmt::CXXForRangeStmtClass: {
5295 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S);
5296 BlockScopeRAII Scope(Info);
5297
5298 // Evaluate the init-statement if present.
5299 if (FS->getInit()) {
5300 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit());
5301 if (ESR != ESR_Succeeded) {
5302 if (ESR != ESR_Failed && !Scope.destroy())
5303 return ESR_Failed;
5304 return ESR;
5305 }
5306 }
5307
5308 // Initialize the __range variable.
5309 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt());
5310 if (ESR != ESR_Succeeded) {
5311 if (ESR != ESR_Failed && !Scope.destroy())
5312 return ESR_Failed;
5313 return ESR;
5314 }
5315
5316 // Create the __begin and __end iterators.
5317 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt());
5318 if (ESR != ESR_Succeeded) {
5319 if (ESR != ESR_Failed && !Scope.destroy())
5320 return ESR_Failed;
5321 return ESR;
5322 }
5323 ESR = EvaluateStmt(Result, Info, FS->getEndStmt());
5324 if (ESR != ESR_Succeeded) {
5325 if (ESR != ESR_Failed && !Scope.destroy())
5326 return ESR_Failed;
5327 return ESR;
5328 }
5329
5330 while (true) {
5331 // Condition: __begin != __end.
5332 {
5333 if (FS->getCond()->isValueDependent()) {
5334 EvaluateDependentExpr(FS->getCond(), Info);
5335 // We don't know whether to keep going or terminate the loop.
5336 return ESR_Failed;
5337 }
5338 bool Continue = true;
5339 FullExpressionRAII CondExpr(Info);
5340 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info))
5341 return ESR_Failed;
5342 if (!Continue)
5343 break;
5344 }
5345
5346 // User's variable declaration, initialized by *__begin.
5347 BlockScopeRAII InnerScope(Info);
5348 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt());
5349 if (ESR != ESR_Succeeded) {
5350 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5351 return ESR_Failed;
5352 return ESR;
5353 }
5354
5355 // Loop body.
5356 ESR = EvaluateLoopBody(Result, Info, FS->getBody());
5357 if (ESR != ESR_Continue) {
5358 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy()))
5359 return ESR_Failed;
5360 return ESR;
5361 }
5362 if (FS->getInc()->isValueDependent()) {
5363 if (!EvaluateDependentExpr(FS->getInc(), Info))
5364 return ESR_Failed;
5365 } else {
5366 // Increment: ++__begin
5367 if (!EvaluateIgnoredValue(Info, FS->getInc()))
5368 return ESR_Failed;
5369 }
5370
5371 if (!InnerScope.destroy())
5372 return ESR_Failed;
5373 }
5374
5375 return Scope.destroy() ? ESR_Succeeded : ESR_Failed;
5376 }
5377
5378 case Stmt::SwitchStmtClass:
5379 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S));
5380
5381 case Stmt::ContinueStmtClass:
5382 return ESR_Continue;
5383
5384 case Stmt::BreakStmtClass:
5385 return ESR_Break;
5386
5387 case Stmt::LabelStmtClass:
5388 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case);
5389
5390 case Stmt::AttributedStmtClass:
5391 // As a general principle, C++11 attributes can be ignored without
5392 // any semantic impact.
5393 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(),
5394 Case);
5395
5396 case Stmt::CaseStmtClass:
5397 case Stmt::DefaultStmtClass:
5398 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case);
5399 case Stmt::CXXTryStmtClass:
5400 // Evaluate try blocks by evaluating all sub statements.
5401 return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case);
5402 }
5403}
5404
5405/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial
5406/// default constructor. If so, we'll fold it whether or not it's marked as
5407/// constexpr. If it is marked as constexpr, we will never implicitly define it,
5408/// so we need special handling.
5409static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
5410 const CXXConstructorDecl *CD,
5411 bool IsValueInitialization) {
5412 if (!CD->isTrivial() || !CD->isDefaultConstructor())
5413 return false;
5414
5415 // Value-initialization does not call a trivial default constructor, so such a
5416 // call is a core constant expression whether or not the constructor is
5417 // constexpr.
5418 if (!CD->isConstexpr() && !IsValueInitialization) {
5419 if (Info.getLangOpts().CPlusPlus11) {
5420 // FIXME: If DiagDecl is an implicitly-declared special member function,
5421 // we should be much more explicit about why it's not constexpr.
5422 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1)
5423 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD;
5424 Info.Note(CD->getLocation(), diag::note_declared_at);
5425 } else {
5426 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr);
5427 }
5428 }
5429 return true;
5430}
5431
5432/// CheckConstexprFunction - Check that a function can be called in a constant
5433/// expression.
5434static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
5435 const FunctionDecl *Declaration,
5436 const FunctionDecl *Definition,
5437 const Stmt *Body) {
5438 // Potential constant expressions can contain calls to declared, but not yet
5439 // defined, constexpr functions.
5440 if (Info.checkingPotentialConstantExpression() && !Definition &&
5441 Declaration->isConstexpr())
5442 return false;
5443
5444 // Bail out if the function declaration itself is invalid. We will
5445 // have produced a relevant diagnostic while parsing it, so just
5446 // note the problematic sub-expression.
5447 if (Declaration->isInvalidDecl()) {
5448 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5449 return false;
5450 }
5451
5452 // DR1872: An instantiated virtual constexpr function can't be called in a
5453 // constant expression (prior to C++20). We can still constant-fold such a
5454 // call.
5455 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) &&
5456 cast<CXXMethodDecl>(Declaration)->isVirtual())
5457 Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call);
5458
5459 if (Definition && Definition->isInvalidDecl()) {
5460 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5461 return false;
5462 }
5463
5464 // Can we evaluate this function call?
5465 if (Definition && Definition->isConstexpr() && Body)
5466 return true;
5467
5468 if (Info.getLangOpts().CPlusPlus11) {
5469 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
5470
5471 // If this function is not constexpr because it is an inherited
5472 // non-constexpr constructor, diagnose that directly.
5473 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
5474 if (CD && CD->isInheritingConstructor()) {
5475 auto *Inherited = CD->getInheritedConstructor().getConstructor();
5476 if (!Inherited->isConstexpr())
5477 DiagDecl = CD = Inherited;
5478 }
5479
5480 // FIXME: If DiagDecl is an implicitly-declared special member function
5481 // or an inheriting constructor, we should be much more explicit about why
5482 // it's not constexpr.
5483 if (CD && CD->isInheritingConstructor())
5484 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1)
5485 << CD->getInheritedConstructor().getConstructor()->getParent();
5486 else
5487 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1)
5488 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl;
5489 Info.Note(DiagDecl->getLocation(), diag::note_declared_at);
5490 } else {
5491 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr);
5492 }
5493 return false;
5494}
5495
5496namespace {
5497struct CheckDynamicTypeHandler {
5498 AccessKinds AccessKind;
5499 typedef bool result_type;
5500 bool failed() { return false; }
5501 bool found(APValue &Subobj, QualType SubobjType) { return true; }
5502 bool found(APSInt &Value, QualType SubobjType) { return true; }
5503 bool found(APFloat &Value, QualType SubobjType) { return true; }
5504};
5505} // end anonymous namespace
5506
5507/// Check that we can access the notional vptr of an object / determine its
5508/// dynamic type.
5509static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
5510 AccessKinds AK, bool Polymorphic) {
5511 if (This.Designator.Invalid)
5512 return false;
5513
5514 CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType());
5515
5516 if (!Obj)
5517 return false;
5518
5519 if (!Obj.Value) {
5520 // The object is not usable in constant expressions, so we can't inspect
5521 // its value to see if it's in-lifetime or what the active union members
5522 // are. We can still check for a one-past-the-end lvalue.
5523 if (This.Designator.isOnePastTheEnd() ||
5524 This.Designator.isMostDerivedAnUnsizedArray()) {
5525 Info.FFDiag(E, This.Designator.isOnePastTheEnd()
5526 ? diag::note_constexpr_access_past_end
5527 : diag::note_constexpr_access_unsized_array)
5528 << AK;
5529 return false;
5530 } else if (Polymorphic) {
5531 // Conservatively refuse to perform a polymorphic operation if we would
5532 // not be able to read a notional 'vptr' value.
5533 APValue Val;
5534 This.moveInto(Val);
5535 QualType StarThisType =
5536 Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx));
5537 Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type)
5538 << AK << Val.getAsString(Info.Ctx, StarThisType);
5539 return false;
5540 }
5541 return true;
5542 }
5543
5544 CheckDynamicTypeHandler Handler{AK};
5545 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
5546}
5547
5548/// Check that the pointee of the 'this' pointer in a member function call is
5549/// either within its lifetime or in its period of construction or destruction.
5550static bool
5551checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E,
5552 const LValue &This,
5553 const CXXMethodDecl *NamedMember) {
5554 return checkDynamicType(
5555 Info, E, This,
5556 isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false);
5557}
5558
5559struct DynamicType {
5560 /// The dynamic class type of the object.
5561 const CXXRecordDecl *Type;
5562 /// The corresponding path length in the lvalue.
5563 unsigned PathLength;
5564};
5565
5566static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator,
5567 unsigned PathLength) {
5568 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <=
5569 Designator.Entries.size() && "invalid path length");
5570 return (PathLength == Designator.MostDerivedPathLength)
5571 ? Designator.MostDerivedType->getAsCXXRecordDecl()
5572 : getAsBaseClass(Designator.Entries[PathLength - 1]);
5573}
5574
5575/// Determine the dynamic type of an object.
5576static Optional<DynamicType> ComputeDynamicType(EvalInfo &Info, const Expr *E,
5577 LValue &This, AccessKinds AK) {
5578 // If we don't have an lvalue denoting an object of class type, there is no
5579 // meaningful dynamic type. (We consider objects of non-class type to have no
5580 // dynamic type.)
5581 if (!checkDynamicType(Info, E, This, AK, true))
5582 return None;
5583
5584 // Refuse to compute a dynamic type in the presence of virtual bases. This
5585 // shouldn't happen other than in constant-folding situations, since literal
5586 // types can't have virtual bases.
5587 //
5588 // Note that consumers of DynamicType assume that the type has no virtual
5589 // bases, and will need modifications if this restriction is relaxed.
5590 const CXXRecordDecl *Class =
5591 This.Designator.MostDerivedType->getAsCXXRecordDecl();
5592 if (!Class || Class->getNumVBases()) {
5593 Info.FFDiag(E);
5594 return None;
5595 }
5596
5597 // FIXME: For very deep class hierarchies, it might be beneficial to use a
5598 // binary search here instead. But the overwhelmingly common case is that
5599 // we're not in the middle of a constructor, so it probably doesn't matter
5600 // in practice.
5601 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries;
5602 for (unsigned PathLength = This.Designator.MostDerivedPathLength;
5603 PathLength <= Path.size(); ++PathLength) {
5604 switch (Info.isEvaluatingCtorDtor(This.getLValueBase(),
5605 Path.slice(0, PathLength))) {
5606 case ConstructionPhase::Bases:
5607 case ConstructionPhase::DestroyingBases:
5608 // We're constructing or destroying a base class. This is not the dynamic
5609 // type.
5610 break;
5611
5612 case ConstructionPhase::None:
5613 case ConstructionPhase::AfterBases:
5614 case ConstructionPhase::AfterFields:
5615 case ConstructionPhase::Destroying:
5616 // We've finished constructing the base classes and not yet started
5617 // destroying them again, so this is the dynamic type.
5618 return DynamicType{getBaseClassType(This.Designator, PathLength),
5619 PathLength};
5620 }
5621 }
5622
5623 // CWG issue 1517: we're constructing a base class of the object described by
5624 // 'This', so that object has not yet begun its period of construction and
5625 // any polymorphic operation on it results in undefined behavior.
5626 Info.FFDiag(E);
5627 return None;
5628}
5629
5630/// Perform virtual dispatch.
5631static const CXXMethodDecl *HandleVirtualDispatch(
5632 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found,
5633 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) {
5634 Optional<DynamicType> DynType = ComputeDynamicType(
5635 Info, E, This,
5636 isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall);
5637 if (!DynType)
5638 return nullptr;
5639
5640 // Find the final overrider. It must be declared in one of the classes on the
5641 // path from the dynamic type to the static type.
5642 // FIXME: If we ever allow literal types to have virtual base classes, that
5643 // won't be true.
5644 const CXXMethodDecl *Callee = Found;
5645 unsigned PathLength = DynType->PathLength;
5646 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) {
5647 const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength);
5648 const CXXMethodDecl *Overrider =
5649 Found->getCorrespondingMethodDeclaredInClass(Class, false);
5650 if (Overrider) {
5651 Callee = Overrider;
5652 break;
5653 }
5654 }
5655
5656 // C++2a [class.abstract]p6:
5657 // the effect of making a virtual call to a pure virtual function [...] is
5658 // undefined
5659 if (Callee->isPure()) {
5660 Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee;
5661 Info.Note(Callee->getLocation(), diag::note_declared_at);
5662 return nullptr;
5663 }
5664
5665 // If necessary, walk the rest of the path to determine the sequence of
5666 // covariant adjustment steps to apply.
5667 if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(),
5668 Found->getReturnType())) {
5669 CovariantAdjustmentPath.push_back(Callee->getReturnType());
5670 for (unsigned CovariantPathLength = PathLength + 1;
5671 CovariantPathLength != This.Designator.Entries.size();
5672 ++CovariantPathLength) {
5673 const CXXRecordDecl *NextClass =
5674 getBaseClassType(This.Designator, CovariantPathLength);
5675 const CXXMethodDecl *Next =
5676 Found->getCorrespondingMethodDeclaredInClass(NextClass, false);
5677 if (Next && !Info.Ctx.hasSameUnqualifiedType(
5678 Next->getReturnType(), CovariantAdjustmentPath.back()))
5679 CovariantAdjustmentPath.push_back(Next->getReturnType());
5680 }
5681 if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(),
5682 CovariantAdjustmentPath.back()))
5683 CovariantAdjustmentPath.push_back(Found->getReturnType());
5684 }
5685
5686 // Perform 'this' adjustment.
5687 if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength))
5688 return nullptr;
5689
5690 return Callee;
5691}
5692
5693/// Perform the adjustment from a value returned by a virtual function to
5694/// a value of the statically expected type, which may be a pointer or
5695/// reference to a base class of the returned type.
5696static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E,
5697 APValue &Result,
5698 ArrayRef<QualType> Path) {
5699 assert(Result.isLValue() &&
5700 "unexpected kind of APValue for covariant return");
5701 if (Result.isNullPointer())
5702 return true;
5703
5704 LValue LVal;
5705 LVal.setFrom(Info.Ctx, Result);
5706
5707 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl();
5708 for (unsigned I = 1; I != Path.size(); ++I) {
5709 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl();
5710 assert(OldClass && NewClass && "unexpected kind of covariant return");
5711 if (OldClass != NewClass &&
5712 !CastToBaseClass(Info, E, LVal, OldClass, NewClass))
5713 return false;
5714 OldClass = NewClass;
5715 }
5716
5717 LVal.moveInto(Result);
5718 return true;
5719}
5720
5721/// Determine whether \p Base, which is known to be a direct base class of
5722/// \p Derived, is a public base class.
5723static bool isBaseClassPublic(const CXXRecordDecl *Derived,
5724 const CXXRecordDecl *Base) {
5725 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) {
5726 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl();
5727 if (BaseClass && declaresSameEntity(BaseClass, Base))
5728 return BaseSpec.getAccessSpecifier() == AS_public;
5729 }
5730 llvm_unreachable("Base is not a direct base of Derived");
5731}
5732
5733/// Apply the given dynamic cast operation on the provided lvalue.
5734///
5735/// This implements the hard case of dynamic_cast, requiring a "runtime check"
5736/// to find a suitable target subobject.
5737static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E,
5738 LValue &Ptr) {
5739 // We can't do anything with a non-symbolic pointer value.
5740 SubobjectDesignator &D = Ptr.Designator;
5741 if (D.Invalid)
5742 return false;
5743
5744 // C++ [expr.dynamic.cast]p6:
5745 // If v is a null pointer value, the result is a null pointer value.
5746 if (Ptr.isNullPointer() && !E->isGLValue())
5747 return true;
5748
5749 // For all the other cases, we need the pointer to point to an object within
5750 // its lifetime / period of construction / destruction, and we need to know
5751 // its dynamic type.
5752 Optional<DynamicType> DynType =
5753 ComputeDynamicType(Info, E, Ptr, AK_DynamicCast);
5754 if (!DynType)
5755 return false;
5756
5757 // C++ [expr.dynamic.cast]p7:
5758 // If T is "pointer to cv void", then the result is a pointer to the most
5759 // derived object
5760 if (E->getType()->isVoidPointerType())
5761 return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength);
5762
5763 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl();
5764 assert(C && "dynamic_cast target is not void pointer nor class");
5765 CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C));
5766
5767 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) {
5768 // C++ [expr.dynamic.cast]p9:
5769 if (!E->isGLValue()) {
5770 // The value of a failed cast to pointer type is the null pointer value
5771 // of the required result type.
5772 Ptr.setNull(Info.Ctx, E->getType());
5773 return true;
5774 }
5775
5776 // A failed cast to reference type throws [...] std::bad_cast.
5777 unsigned DiagKind;
5778 if (!Paths && (declaresSameEntity(DynType->Type, C) ||
5779 DynType->Type->isDerivedFrom(C)))
5780 DiagKind = 0;
5781 else if (!Paths || Paths->begin() == Paths->end())
5782 DiagKind = 1;
5783 else if (Paths->isAmbiguous(CQT))
5784 DiagKind = 2;
5785 else {
5786 assert(Paths->front().Access != AS_public && "why did the cast fail?");
5787 DiagKind = 3;
5788 }
5789 Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed)
5790 << DiagKind << Ptr.Designator.getType(Info.Ctx)
5791 << Info.Ctx.getRecordType(DynType->Type)
5792 << E->getType().getUnqualifiedType();
5793 return false;
5794 };
5795
5796 // Runtime check, phase 1:
5797 // Walk from the base subobject towards the derived object looking for the
5798 // target type.
5799 for (int PathLength = Ptr.Designator.Entries.size();
5800 PathLength >= (int)DynType->PathLength; --PathLength) {
5801 const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength);
5802 if (declaresSameEntity(Class, C))
5803 return CastToDerivedClass(Info, E, Ptr, Class, PathLength);
5804 // We can only walk across public inheritance edges.
5805 if (PathLength > (int)DynType->PathLength &&
5806 !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1),
5807 Class))
5808 return RuntimeCheckFailed(nullptr);
5809 }
5810
5811 // Runtime check, phase 2:
5812 // Search the dynamic type for an unambiguous public base of type C.
5813 CXXBasePaths Paths(/*FindAmbiguities=*/true,
5814 /*RecordPaths=*/true, /*DetectVirtual=*/false);
5815 if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) &&
5816 Paths.front().Access == AS_public) {
5817 // Downcast to the dynamic type...
5818 if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength))
5819 return false;
5820 // ... then upcast to the chosen base class subobject.
5821 for (CXXBasePathElement &Elem : Paths.front())
5822 if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base))
5823 return false;
5824 return true;
5825 }
5826
5827 // Otherwise, the runtime check fails.
5828 return RuntimeCheckFailed(&Paths);
5829}
5830
5831namespace {
5832struct StartLifetimeOfUnionMemberHandler {
5833 EvalInfo &Info;
5834 const Expr *LHSExpr;
5835 const FieldDecl *Field;
5836 bool DuringInit;
5837 bool Failed = false;
5838 static const AccessKinds AccessKind = AK_Assign;
5839
5840 typedef bool result_type;
5841 bool failed() { return Failed; }
5842 bool found(APValue &Subobj, QualType SubobjType) {
5843 // We are supposed to perform no initialization but begin the lifetime of
5844 // the object. We interpret that as meaning to do what default
5845 // initialization of the object would do if all constructors involved were
5846 // trivial:
5847 // * All base, non-variant member, and array element subobjects' lifetimes
5848 // begin
5849 // * No variant members' lifetimes begin
5850 // * All scalar subobjects whose lifetimes begin have indeterminate values
5851 assert(SubobjType->isUnionType());
5852 if (declaresSameEntity(Subobj.getUnionField(), Field)) {
5853 // This union member is already active. If it's also in-lifetime, there's
5854 // nothing to do.
5855 if (Subobj.getUnionValue().hasValue())
5856 return true;
5857 } else if (DuringInit) {
5858 // We're currently in the process of initializing a different union
5859 // member. If we carried on, that initialization would attempt to
5860 // store to an inactive union member, resulting in undefined behavior.
5861 Info.FFDiag(LHSExpr,
5862 diag::note_constexpr_union_member_change_during_init);
5863 return false;
5864 }
5865 APValue Result;
5866 Failed = !getDefaultInitValue(Field->getType(), Result);
5867 Subobj.setUnion(Field, Result);
5868 return true;
5869 }
5870 bool found(APSInt &Value, QualType SubobjType) {
5871 llvm_unreachable("wrong value kind for union object");
5872 }
5873 bool found(APFloat &Value, QualType SubobjType) {
5874 llvm_unreachable("wrong value kind for union object");
5875 }
5876};
5877} // end anonymous namespace
5878
5879const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind;
5880
5881/// Handle a builtin simple-assignment or a call to a trivial assignment
5882/// operator whose left-hand side might involve a union member access. If it
5883/// does, implicitly start the lifetime of any accessed union elements per
5884/// C++20 [class.union]5.
5885static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr,
5886 const LValue &LHS) {
5887 if (LHS.InvalidBase || LHS.Designator.Invalid)
5888 return false;
5889
5890 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths;
5891 // C++ [class.union]p5:
5892 // define the set S(E) of subexpressions of E as follows:
5893 unsigned PathLength = LHS.Designator.Entries.size();
5894 for (const Expr *E = LHSExpr; E != nullptr;) {
5895 // -- If E is of the form A.B, S(E) contains the elements of S(A)...
5896 if (auto *ME = dyn_cast<MemberExpr>(E)) {
5897 auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
5898 // Note that we can't implicitly start the lifetime of a reference,
5899 // so we don't need to proceed any further if we reach one.
5900 if (!FD || FD->getType()->isReferenceType())
5901 break;
5902
5903 // ... and also contains A.B if B names a union member ...
5904 if (FD->getParent()->isUnion()) {
5905 // ... of a non-class, non-array type, or of a class type with a
5906 // trivial default constructor that is not deleted, or an array of
5907 // such types.
5908 auto *RD =
5909 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
5910 if (!RD || RD->hasTrivialDefaultConstructor())
5911 UnionPathLengths.push_back({PathLength - 1, FD});
5912 }
5913
5914 E = ME->getBase();
5915 --PathLength;
5916 assert(declaresSameEntity(FD,
5917 LHS.Designator.Entries[PathLength]
5918 .getAsBaseOrMember().getPointer()));
5919
5920 // -- If E is of the form A[B] and is interpreted as a built-in array
5921 // subscripting operator, S(E) is [S(the array operand, if any)].
5922 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) {
5923 // Step over an ArrayToPointerDecay implicit cast.
5924 auto *Base = ASE->getBase()->IgnoreImplicit();
5925 if (!Base->getType()->isArrayType())
5926 break;
5927
5928 E = Base;
5929 --PathLength;
5930
5931 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) {
5932 // Step over a derived-to-base conversion.
5933 E = ICE->getSubExpr();
5934 if (ICE->getCastKind() == CK_NoOp)
5935 continue;
5936 if (ICE->getCastKind() != CK_DerivedToBase &&
5937 ICE->getCastKind() != CK_UncheckedDerivedToBase)
5938 break;
5939 // Walk path backwards as we walk up from the base to the derived class.
5940 for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) {
5941 --PathLength;
5942 (void)Elt;
5943 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(),
5944 LHS.Designator.Entries[PathLength]
5945 .getAsBaseOrMember().getPointer()));
5946 }
5947
5948 // -- Otherwise, S(E) is empty.
5949 } else {
5950 break;
5951 }
5952 }
5953
5954 // Common case: no unions' lifetimes are started.
5955 if (UnionPathLengths.empty())
5956 return true;
5957
5958 // if modification of X [would access an inactive union member], an object
5959 // of the type of X is implicitly created
5960 CompleteObject Obj =
5961 findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType());
5962 if (!Obj)
5963 return false;
5964 for (std::pair<unsigned, const FieldDecl *> LengthAndField :
5965 llvm::reverse(UnionPathLengths)) {
5966 // Form a designator for the union object.
5967 SubobjectDesignator D = LHS.Designator;
5968 D.truncate(Info.Ctx, LHS.Base, LengthAndField.first);
5969
5970 bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) ==
5971 ConstructionPhase::AfterBases;
5972 StartLifetimeOfUnionMemberHandler StartLifetime{
5973 Info, LHSExpr, LengthAndField.second, DuringInit};
5974 if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime))
5975 return false;
5976 }
5977
5978 return true;
5979}
5980
5981static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg,
5982 CallRef Call, EvalInfo &Info,
5983 bool NonNull = false) {
5984 LValue LV;
5985 // Create the parameter slot and register its destruction. For a vararg
5986 // argument, create a temporary.
5987 // FIXME: For calling conventions that destroy parameters in the callee,
5988 // should we consider performing destruction when the function returns
5989 // instead?
5990 APValue &V = PVD ? Info.CurrentCall->createParam(Call, PVD, LV)
5991 : Info.CurrentCall->createTemporary(Arg, Arg->getType(),
5992 ScopeKind::Call, LV);
5993 if (!EvaluateInPlace(V, Info, LV, Arg))
5994 return false;
5995
5996 // Passing a null pointer to an __attribute__((nonnull)) parameter results in
5997 // undefined behavior, so is non-constant.
5998 if (NonNull && V.isLValue() && V.isNullPointer()) {
5999 Info.CCEDiag(Arg, diag::note_non_null_attribute_failed);
6000 return false;
6001 }
6002
6003 return true;
6004}
6005
6006/// Evaluate the arguments to a function call.
6007static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call,
6008 EvalInfo &Info, const FunctionDecl *Callee,
6009 bool RightToLeft = false) {
6010 bool Success = true;
6011 llvm::SmallBitVector ForbiddenNullArgs;
6012 if (Callee->hasAttr<NonNullAttr>()) {
6013 ForbiddenNullArgs.resize(Args.size());
6014 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) {
6015 if (!Attr->args_size()) {
6016 ForbiddenNullArgs.set();
6017 break;
6018 } else
6019 for (auto Idx : Attr->args()) {
6020 unsigned ASTIdx = Idx.getASTIndex();
6021 if (ASTIdx >= Args.size())
6022 continue;
6023 ForbiddenNullArgs[ASTIdx] = 1;
6024 }
6025 }
6026 }
6027 for (unsigned I = 0; I < Args.size(); I++) {
6028 unsigned Idx = RightToLeft ? Args.size() - I - 1 : I;
6029 const ParmVarDecl *PVD =
6030 Idx < Callee->getNumParams() ? Callee->getParamDecl(Idx) : nullptr;
6031 bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx];
6032 if (!EvaluateCallArg(PVD, Args[Idx], Call, Info, NonNull)) {
6033 // If we're checking for a potential constant expression, evaluate all
6034 // initializers even if some of them fail.
6035 if (!Info.noteFailure())
6036 return false;
6037 Success = false;
6038 }
6039 }
6040 return Success;
6041}
6042
6043/// Perform a trivial copy from Param, which is the parameter of a copy or move
6044/// constructor or assignment operator.
6045static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param,
6046 const Expr *E, APValue &Result,
6047 bool CopyObjectRepresentation) {
6048 // Find the reference argument.
6049 CallStackFrame *Frame = Info.CurrentCall;
6050 APValue *RefValue = Info.getParamSlot(Frame->Arguments, Param);
6051 if (!RefValue) {
6052 Info.FFDiag(E);
6053 return false;
6054 }
6055
6056 // Copy out the contents of the RHS object.
6057 LValue RefLValue;
6058 RefLValue.setFrom(Info.Ctx, *RefValue);
6059 return handleLValueToRValueConversion(
6060 Info, E, Param->getType().getNonReferenceType(), RefLValue, Result,
6061 CopyObjectRepresentation);
6062}
6063
6064/// Evaluate a function call.
6065static bool HandleFunctionCall(SourceLocation CallLoc,
6066 const FunctionDecl *Callee, const LValue *This,
6067 ArrayRef<const Expr *> Args, CallRef Call,
6068 const Stmt *Body, EvalInfo &Info,
6069 APValue &Result, const LValue *ResultSlot) {
6070 if (!Info.CheckCallLimit(CallLoc))
6071 return false;
6072
6073 CallStackFrame Frame(Info, CallLoc, Callee, This, Call);
6074
6075 // For a trivial copy or move assignment, perform an APValue copy. This is
6076 // essential for unions, where the operations performed by the assignment
6077 // operator cannot be represented as statements.
6078 //
6079 // Skip this for non-union classes with no fields; in that case, the defaulted
6080 // copy/move does not actually read the object.
6081 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee);
6082 if (MD && MD->isDefaulted() &&
6083 (MD->getParent()->isUnion() ||
6084 (MD->isTrivial() &&
6085 isReadByLvalueToRvalueConversion(MD->getParent())))) {
6086 assert(This &&
6087 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()));
6088 APValue RHSValue;
6089 if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue,
6090 MD->getParent()->isUnion()))
6091 return false;
6092 if (Info.getLangOpts().CPlusPlus20 && MD->isTrivial() &&
6093 !HandleUnionActiveMemberChange(Info, Args[0], *This))
6094 return false;
6095 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(),
6096 RHSValue))
6097 return false;
6098 This->moveInto(Result);
6099 return true;
6100 } else if (MD && isLambdaCallOperator(MD)) {
6101 // We're in a lambda; determine the lambda capture field maps unless we're
6102 // just constexpr checking a lambda's call operator. constexpr checking is
6103 // done before the captures have been added to the closure object (unless
6104 // we're inferring constexpr-ness), so we don't have access to them in this
6105 // case. But since we don't need the captures to constexpr check, we can
6106 // just ignore them.
6107 if (!Info.checkingPotentialConstantExpression())
6108 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields,
6109 Frame.LambdaThisCaptureField);
6110 }
6111
6112 StmtResult Ret = {Result, ResultSlot};
6113 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body);
6114 if (ESR == ESR_Succeeded) {
6115 if (Callee->getReturnType()->isVoidType())
6116 return true;
6117 Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return);
6118 }
6119 return ESR == ESR_Returned;
6120}
6121
6122/// Evaluate a constructor call.
6123static bool HandleConstructorCall(const Expr *E, const LValue &This,
6124 CallRef Call,
6125 const CXXConstructorDecl *Definition,
6126 EvalInfo &Info, APValue &Result) {
6127 SourceLocation CallLoc = E->getExprLoc();
6128 if (!Info.CheckCallLimit(CallLoc))
6129 return false;
6130
6131 const CXXRecordDecl *RD = Definition->getParent();
6132 if (RD->getNumVBases()) {
6133 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6134 return false;
6135 }
6136
6137 EvalInfo::EvaluatingConstructorRAII EvalObj(
6138 Info,
6139 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
6140 RD->getNumBases());
6141 CallStackFrame Frame(Info, CallLoc, Definition, &This, Call);
6142
6143 // FIXME: Creating an APValue just to hold a nonexistent return value is
6144 // wasteful.
6145 APValue RetVal;
6146 StmtResult Ret = {RetVal, nullptr};
6147
6148 // If it's a delegating constructor, delegate.
6149 if (Definition->isDelegatingConstructor()) {
6150 CXXConstructorDecl::init_const_iterator I = Definition->init_begin();
6151 if ((*I)->getInit()->isValueDependent()) {
6152 if (!EvaluateDependentExpr((*I)->getInit(), Info))
6153 return false;
6154 } else {
6155 FullExpressionRAII InitScope(Info);
6156 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) ||
6157 !InitScope.destroy())
6158 return false;
6159 }
6160 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed;
6161 }
6162
6163 // For a trivial copy or move constructor, perform an APValue copy. This is
6164 // essential for unions (or classes with anonymous union members), where the
6165 // operations performed by the constructor cannot be represented by
6166 // ctor-initializers.
6167 //
6168 // Skip this for empty non-union classes; we should not perform an
6169 // lvalue-to-rvalue conversion on them because their copy constructor does not
6170 // actually read them.
6171 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() &&
6172 (Definition->getParent()->isUnion() ||
6173 (Definition->isTrivial() &&
6174 isReadByLvalueToRvalueConversion(Definition->getParent())))) {
6175 return handleTrivialCopy(Info, Definition->getParamDecl(0), E, Result,
6176 Definition->getParent()->isUnion());
6177 }
6178
6179 // Reserve space for the struct members.
6180 if (!Result.hasValue()) {
6181 if (!RD->isUnion())
6182 Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
6183 std::distance(RD->field_begin(), RD->field_end()));
6184 else
6185 // A union starts with no active member.
6186 Result = APValue((const FieldDecl*)nullptr);
6187 }
6188
6189 if (RD->isInvalidDecl()) return false;
6190 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6191
6192 // A scope for temporaries lifetime-extended by reference members.
6193 BlockScopeRAII LifetimeExtendedScope(Info);
6194
6195 bool Success = true;
6196 unsigned BasesSeen = 0;
6197#ifndef NDEBUG
6198 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin();
6199#endif
6200 CXXRecordDecl::field_iterator FieldIt = RD->field_begin();
6201 auto SkipToField = [&](FieldDecl *FD, bool Indirect) {
6202 // We might be initializing the same field again if this is an indirect
6203 // field initialization.
6204 if (FieldIt == RD->field_end() ||
6205 FieldIt->getFieldIndex() > FD->getFieldIndex()) {
6206 assert(Indirect && "fields out of order?");
6207 return;
6208 }
6209
6210 // Default-initialize any fields with no explicit initializer.
6211 for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) {
6212 assert(FieldIt != RD->field_end() && "missing field?");
6213 if (!FieldIt->isUnnamedBitfield())
6214 Success &= getDefaultInitValue(
6215 FieldIt->getType(),
6216 Result.getStructField(FieldIt->getFieldIndex()));
6217 }
6218 ++FieldIt;
6219 };
6220 for (const auto *I : Definition->inits()) {
6221 LValue Subobject = This;
6222 LValue SubobjectParent = This;
6223 APValue *Value = &Result;
6224
6225 // Determine the subobject to initialize.
6226 FieldDecl *FD = nullptr;
6227 if (I->isBaseInitializer()) {
6228 QualType BaseType(I->getBaseClass(), 0);
6229#ifndef NDEBUG
6230 // Non-virtual base classes are initialized in the order in the class
6231 // definition. We have already checked for virtual base classes.
6232 assert(!BaseIt->isVirtual() && "virtual base for literal type");
6233 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) &&
6234 "base class initializers not in expected order");
6235 ++BaseIt;
6236#endif
6237 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD,
6238 BaseType->getAsCXXRecordDecl(), &Layout))
6239 return false;
6240 Value = &Result.getStructBase(BasesSeen++);
6241 } else if ((FD = I->getMember())) {
6242 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout))
6243 return false;
6244 if (RD->isUnion()) {
6245 Result = APValue(FD);
6246 Value = &Result.getUnionValue();
6247 } else {
6248 SkipToField(FD, false);
6249 Value = &Result.getStructField(FD->getFieldIndex());
6250 }
6251 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) {
6252 // Walk the indirect field decl's chain to find the object to initialize,
6253 // and make sure we've initialized every step along it.
6254 auto IndirectFieldChain = IFD->chain();
6255 for (auto *C : IndirectFieldChain) {
6256 FD = cast<FieldDecl>(C);
6257 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent());
6258 // Switch the union field if it differs. This happens if we had
6259 // preceding zero-initialization, and we're now initializing a union
6260 // subobject other than the first.
6261 // FIXME: In this case, the values of the other subobjects are
6262 // specified, since zero-initialization sets all padding bits to zero.
6263 if (!Value->hasValue() ||
6264 (Value->isUnion() && Value->getUnionField() != FD)) {
6265 if (CD->isUnion())
6266 *Value = APValue(FD);
6267 else
6268 // FIXME: This immediately starts the lifetime of all members of
6269 // an anonymous struct. It would be preferable to strictly start
6270 // member lifetime in initialization order.
6271 Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value);
6272 }
6273 // Store Subobject as its parent before updating it for the last element
6274 // in the chain.
6275 if (C == IndirectFieldChain.back())
6276 SubobjectParent = Subobject;
6277 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD))
6278 return false;
6279 if (CD->isUnion())
6280 Value = &Value->getUnionValue();
6281 else {
6282 if (C == IndirectFieldChain.front() && !RD->isUnion())
6283 SkipToField(FD, true);
6284 Value = &Value->getStructField(FD->getFieldIndex());
6285 }
6286 }
6287 } else {
6288 llvm_unreachable("unknown base initializer kind");
6289 }
6290
6291 // Need to override This for implicit field initializers as in this case
6292 // This refers to innermost anonymous struct/union containing initializer,
6293 // not to currently constructed class.
6294 const Expr *Init = I->getInit();
6295 if (Init->isValueDependent()) {
6296 if (!EvaluateDependentExpr(Init, Info))
6297 return false;
6298 } else {
6299 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent,
6300 isa<CXXDefaultInitExpr>(Init));
6301 FullExpressionRAII InitScope(Info);
6302 if (!EvaluateInPlace(*Value, Info, Subobject, Init) ||
6303 (FD && FD->isBitField() &&
6304 !truncateBitfieldValue(Info, Init, *Value, FD))) {
6305 // If we're checking for a potential constant expression, evaluate all
6306 // initializers even if some of them fail.
6307 if (!Info.noteFailure())
6308 return false;
6309 Success = false;
6310 }
6311 }
6312
6313 // This is the point at which the dynamic type of the object becomes this
6314 // class type.
6315 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases())
6316 EvalObj.finishedConstructingBases();
6317 }
6318
6319 // Default-initialize any remaining fields.
6320 if (!RD->isUnion()) {
6321 for (; FieldIt != RD->field_end(); ++FieldIt) {
6322 if (!FieldIt->isUnnamedBitfield())
6323 Success &= getDefaultInitValue(
6324 FieldIt->getType(),
6325 Result.getStructField(FieldIt->getFieldIndex()));
6326 }
6327 }
6328
6329 EvalObj.finishedConstructingFields();
6330
6331 return Success &&
6332 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed &&
6333 LifetimeExtendedScope.destroy();
6334}
6335
6336static bool HandleConstructorCall(const Expr *E, const LValue &This,
6337 ArrayRef<const Expr*> Args,
6338 const CXXConstructorDecl *Definition,
6339 EvalInfo &Info, APValue &Result) {
6340 CallScopeRAII CallScope(Info);
6341 CallRef Call = Info.CurrentCall->createCall(Definition);
6342 if (!EvaluateArgs(Args, Call, Info, Definition))
6343 return false;
6344
6345 return HandleConstructorCall(E, This, Call, Definition, Info, Result) &&
6346 CallScope.destroy();
6347}
6348
6349static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc,
6350 const LValue &This, APValue &Value,
6351 QualType T) {
6352 // Objects can only be destroyed while they're within their lifetimes.
6353 // FIXME: We have no representation for whether an object of type nullptr_t
6354 // is in its lifetime; it usually doesn't matter. Perhaps we should model it
6355 // as indeterminate instead?
6356 if (Value.isAbsent() && !T->isNullPtrType()) {
6357 APValue Printable;
6358 This.moveInto(Printable);
6359 Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime)
6360 << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T));
6361 return false;
6362 }
6363
6364 // Invent an expression for location purposes.
6365 // FIXME: We shouldn't need to do this.
6366 OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_RValue);
6367
6368 // For arrays, destroy elements right-to-left.
6369 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) {
6370 uint64_t Size = CAT->getSize().getZExtValue();
6371 QualType ElemT = CAT->getElementType();
6372
6373 LValue ElemLV = This;
6374 ElemLV.addArray(Info, &LocE, CAT);
6375 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size))
6376 return false;
6377
6378 // Ensure that we have actual array elements available to destroy; the
6379 // destructors might mutate the value, so we can't run them on the array
6380 // filler.
6381 if (Size && Size > Value.getArrayInitializedElts())
6382 expandArray(Value, Value.getArraySize() - 1);
6383
6384 for (; Size != 0; --Size) {
6385 APValue &Elem = Value.getArrayInitializedElt(Size - 1);
6386 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) ||
6387 !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT))
6388 return false;
6389 }
6390
6391 // End the lifetime of this array now.
6392 Value = APValue();
6393 return true;
6394 }
6395
6396 const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
6397 if (!RD) {
6398 if (T.isDestructedType()) {
6399 Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T;
6400 return false;
6401 }
6402
6403 Value = APValue();
6404 return true;
6405 }
6406
6407 if (RD->getNumVBases()) {
6408 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD;
6409 return false;
6410 }
6411
6412 const CXXDestructorDecl *DD = RD->getDestructor();
6413 if (!DD && !RD->hasTrivialDestructor()) {
6414 Info.FFDiag(CallLoc);
6415 return false;
6416 }
6417
6418 if (!DD || DD->isTrivial() ||
6419 (RD->isAnonymousStructOrUnion() && RD->isUnion())) {
6420 // A trivial destructor just ends the lifetime of the object. Check for
6421 // this case before checking for a body, because we might not bother
6422 // building a body for a trivial destructor. Note that it doesn't matter
6423 // whether the destructor is constexpr in this case; all trivial
6424 // destructors are constexpr.
6425 //
6426 // If an anonymous union would be destroyed, some enclosing destructor must
6427 // have been explicitly defined, and the anonymous union destruction should
6428 // have no effect.
6429 Value = APValue();
6430 return true;
6431 }
6432
6433 if (!Info.CheckCallLimit(CallLoc))
6434 return false;
6435
6436 const FunctionDecl *Definition = nullptr;
6437 const Stmt *Body = DD->getBody(Definition);
6438
6439 if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body))
6440 return false;
6441
6442 CallStackFrame Frame(Info, CallLoc, Definition, &This, CallRef());
6443
6444 // We're now in the period of destruction of this object.
6445 unsigned BasesLeft = RD->getNumBases();
6446 EvalInfo::EvaluatingDestructorRAII EvalObj(
6447 Info,
6448 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries});
6449 if (!EvalObj.DidInsert) {
6450 // C++2a [class.dtor]p19:
6451 // the behavior is undefined if the destructor is invoked for an object
6452 // whose lifetime has ended
6453 // (Note that formally the lifetime ends when the period of destruction
6454 // begins, even though certain uses of the object remain valid until the
6455 // period of destruction ends.)
6456 Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy);
6457 return false;
6458 }
6459
6460 // FIXME: Creating an APValue just to hold a nonexistent return value is
6461 // wasteful.
6462 APValue RetVal;
6463 StmtResult Ret = {RetVal, nullptr};
6464 if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed)
6465 return false;
6466
6467 // A union destructor does not implicitly destroy its members.
6468 if (RD->isUnion())
6469 return true;
6470
6471 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6472
6473 // We don't have a good way to iterate fields in reverse, so collect all the
6474 // fields first and then walk them backwards.
6475 SmallVector<FieldDecl*, 16> Fields(RD->field_begin(), RD->field_end());
6476 for (const FieldDecl *FD : llvm::reverse(Fields)) {
6477 if (FD->isUnnamedBitfield())
6478 continue;
6479
6480 LValue Subobject = This;
6481 if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout))
6482 return false;
6483
6484 APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex());
6485 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6486 FD->getType()))
6487 return false;
6488 }
6489
6490 if (BasesLeft != 0)
6491 EvalObj.startedDestroyingBases();
6492
6493 // Destroy base classes in reverse order.
6494 for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) {
6495 --BasesLeft;
6496
6497 QualType BaseType = Base.getType();
6498 LValue Subobject = This;
6499 if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD,
6500 BaseType->getAsCXXRecordDecl(), &Layout))
6501 return false;
6502
6503 APValue *SubobjectValue = &Value.getStructBase(BasesLeft);
6504 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue,
6505 BaseType))
6506 return false;
6507 }
6508 assert(BasesLeft == 0 && "NumBases was wrong?");
6509
6510 // The period of destruction ends now. The object is gone.
6511 Value = APValue();
6512 return true;
6513}
6514
6515namespace {
6516struct DestroyObjectHandler {
6517 EvalInfo &Info;
6518 const Expr *E;
6519 const LValue &This;
6520 const AccessKinds AccessKind;
6521
6522 typedef bool result_type;
6523 bool failed() { return false; }
6524 bool found(APValue &Subobj, QualType SubobjType) {
6525 return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj,
6526 SubobjType);
6527 }
6528 bool found(APSInt &Value, QualType SubobjType) {
6529 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6530 return false;
6531 }
6532 bool found(APFloat &Value, QualType SubobjType) {
6533 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem);
6534 return false;
6535 }
6536};
6537}
6538
6539/// Perform a destructor or pseudo-destructor call on the given object, which
6540/// might in general not be a complete object.
6541static bool HandleDestruction(EvalInfo &Info, const Expr *E,
6542 const LValue &This, QualType ThisType) {
6543 CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType);
6544 DestroyObjectHandler Handler = {Info, E, This, AK_Destroy};
6545 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler);
6546}
6547
6548/// Destroy and end the lifetime of the given complete object.
6549static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc,
6550 APValue::LValueBase LVBase, APValue &Value,
6551 QualType T) {
6552 // If we've had an unmodeled side-effect, we can't rely on mutable state
6553 // (such as the object we're about to destroy) being correct.
6554 if (Info.EvalStatus.HasSideEffects)
6555 return false;
6556
6557 LValue LV;
6558 LV.set({LVBase});
6559 return HandleDestructionImpl(Info, Loc, LV, Value, T);
6560}
6561
6562/// Perform a call to 'perator new' or to `__builtin_operator_new'.
6563static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E,
6564 LValue &Result) {
6565 if (Info.checkingPotentialConstantExpression() ||
6566 Info.SpeculativeEvaluationDepth)
6567 return false;
6568
6569 // This is permitted only within a call to std::allocator<T>::allocate.
6570 auto Caller = Info.getStdAllocatorCaller("allocate");
6571 if (!Caller) {
6572 Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20
6573 ? diag::note_constexpr_new_untyped
6574 : diag::note_constexpr_new);
6575 return false;
6576 }
6577
6578 QualType ElemType = Caller.ElemType;
6579 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) {
6580 Info.FFDiag(E->getExprLoc(),
6581 diag::note_constexpr_new_not_complete_object_type)
6582 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType;
6583 return false;
6584 }
6585
6586 APSInt ByteSize;
6587 if (!EvaluateInteger(E->getArg(0), ByteSize, Info))
6588 return false;
6589 bool IsNothrow = false;
6590 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) {
6591 EvaluateIgnoredValue(Info, E->getArg(I));
6592 IsNothrow |= E->getType()->isNothrowT();
6593 }
6594
6595 CharUnits ElemSize;
6596 if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize))
6597 return false;
6598 APInt Size, Remainder;
6599 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity());
6600 APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder);
6601 if (Remainder != 0) {
6602 // This likely indicates a bug in the implementation of 'std::allocator'.
6603 Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size)
6604 << ByteSize << APSInt(ElemSizeAP, true) << ElemType;
6605 return false;
6606 }
6607
6608 if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
6609 if (IsNothrow) {
6610 Result.setNull(Info.Ctx, E->getType());
6611 return true;
6612 }
6613
6614 Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true);
6615 return false;
6616 }
6617
6618 QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr,
6619 ArrayType::Normal, 0);
6620 APValue *Val = Info.createHeapAlloc(E, AllocType, Result);
6621 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue());
6622 Result.addArray(Info, E, cast<ConstantArrayType>(AllocType));
6623 return true;
6624}
6625
6626static bool hasVirtualDestructor(QualType T) {
6627 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6628 if (CXXDestructorDecl *DD = RD->getDestructor())
6629 return DD->isVirtual();
6630 return false;
6631}
6632
6633static const FunctionDecl *getVirtualOperatorDelete(QualType T) {
6634 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
6635 if (CXXDestructorDecl *DD = RD->getDestructor())
6636 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr;
6637 return nullptr;
6638}
6639
6640/// Check that the given object is a suitable pointer to a heap allocation that
6641/// still exists and is of the right kind for the purpose of a deletion.
6642///
6643/// On success, returns the heap allocation to deallocate. On failure, produces
6644/// a diagnostic and returns None.
6645static Optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E,
6646 const LValue &Pointer,
6647 DynAlloc::Kind DeallocKind) {
6648 auto PointerAsString = [&] {
6649 return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy);
6650 };
6651
6652 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>();
6653 if (!DA) {
6654 Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc)
6655 << PointerAsString();
6656 if (Pointer.Base)
6657 NoteLValueLocation(Info, Pointer.Base);
6658 return None;
6659 }
6660
6661 Optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
6662 if (!Alloc) {
6663 Info.FFDiag(E, diag::note_constexpr_double_delete);
6664 return None;
6665 }
6666
6667 QualType AllocType = Pointer.Base.getDynamicAllocType();
6668 if (DeallocKind != (*Alloc)->getKind()) {
6669 Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch)
6670 << DeallocKind << (*Alloc)->getKind() << AllocType;
6671 NoteLValueLocation(Info, Pointer.Base);
6672 return None;
6673 }
6674
6675 bool Subobject = false;
6676 if (DeallocKind == DynAlloc::New) {
6677 Subobject = Pointer.Designator.MostDerivedPathLength != 0 ||
6678 Pointer.Designator.isOnePastTheEnd();
6679 } else {
6680 Subobject = Pointer.Designator.Entries.size() != 1 ||
6681 Pointer.Designator.Entries[0].getAsArrayIndex() != 0;
6682 }
6683 if (Subobject) {
6684 Info.FFDiag(E, diag::note_constexpr_delete_subobject)
6685 << PointerAsString() << Pointer.Designator.isOnePastTheEnd();
6686 return None;
6687 }
6688
6689 return Alloc;
6690}
6691
6692// Perform a call to 'operator delete' or '__builtin_operator_delete'.
6693bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) {
6694 if (Info.checkingPotentialConstantExpression() ||
6695 Info.SpeculativeEvaluationDepth)
6696 return false;
6697
6698 // This is permitted only within a call to std::allocator<T>::deallocate.
6699 if (!Info.getStdAllocatorCaller("deallocate")) {
6700 Info.FFDiag(E->getExprLoc());
6701 return true;
6702 }
6703
6704 LValue Pointer;
6705 if (!EvaluatePointer(E->getArg(0), Pointer, Info))
6706 return false;
6707 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I)
6708 EvaluateIgnoredValue(Info, E->getArg(I));
6709
6710 if (Pointer.Designator.Invalid)
6711 return false;
6712
6713 // Deleting a null pointer has no effect.
6714 if (Pointer.isNullPointer())
6715 return true;
6716
6717 if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator))
6718 return false;
6719
6720 Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>());
6721 return true;
6722}
6723
6724//===----------------------------------------------------------------------===//
6725// Generic Evaluation
6726//===----------------------------------------------------------------------===//
6727namespace {
6728
6729class BitCastBuffer {
6730 // FIXME: We're going to need bit-level granularity when we support
6731 // bit-fields.
6732 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but
6733 // we don't support a host or target where that is the case. Still, we should
6734 // use a more generic type in case we ever do.
6735 SmallVector<Optional<unsigned char>, 32> Bytes;
6736
6737 static_assert(std::numeric_limits<unsigned char>::digits >= 8,
6738 "Need at least 8 bit unsigned char");
6739
6740 bool TargetIsLittleEndian;
6741
6742public:
6743 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian)
6744 : Bytes(Width.getQuantity()),
6745 TargetIsLittleEndian(TargetIsLittleEndian) {}
6746
6747 LLVM_NODISCARD
6748 bool readObject(CharUnits Offset, CharUnits Width,
6749 SmallVectorImpl<unsigned char> &Output) const {
6750 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) {
6751 // If a byte of an integer is uninitialized, then the whole integer is
6752 // uninitalized.
6753 if (!Bytes[I.getQuantity()])
6754 return false;
6755 Output.push_back(*Bytes[I.getQuantity()]);
6756 }
6757 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6758 std::reverse(Output.begin(), Output.end());
6759 return true;
6760 }
6761
6762 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) {
6763 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian)
6764 std::reverse(Input.begin(), Input.end());
6765
6766 size_t Index = 0;
6767 for (unsigned char Byte : Input) {
6768 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?");
6769 Bytes[Offset.getQuantity() + Index] = Byte;
6770 ++Index;
6771 }
6772 }
6773
6774 size_t size() { return Bytes.size(); }
6775};
6776
6777/// Traverse an APValue to produce an BitCastBuffer, emulating how the current
6778/// target would represent the value at runtime.
6779class APValueToBufferConverter {
6780 EvalInfo &Info;
6781 BitCastBuffer Buffer;
6782 const CastExpr *BCE;
6783
6784 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth,
6785 const CastExpr *BCE)
6786 : Info(Info),
6787 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()),
6788 BCE(BCE) {}
6789
6790 bool visit(const APValue &Val, QualType Ty) {
6791 return visit(Val, Ty, CharUnits::fromQuantity(0));
6792 }
6793
6794 // Write out Val with type Ty into Buffer starting at Offset.
6795 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) {
6796 assert((size_t)Offset.getQuantity() <= Buffer.size());
6797
6798 // As a special case, nullptr_t has an indeterminate value.
6799 if (Ty->isNullPtrType())
6800 return true;
6801
6802 // Dig through Src to find the byte at SrcOffset.
6803 switch (Val.getKind()) {
6804 case APValue::Indeterminate:
6805 case APValue::None:
6806 return true;
6807
6808 case APValue::Int:
6809 return visitInt(Val.getInt(), Ty, Offset);
6810 case APValue::Float:
6811 return visitFloat(Val.getFloat(), Ty, Offset);
6812 case APValue::Array:
6813 return visitArray(Val, Ty, Offset);
6814 case APValue::Struct:
6815 return visitRecord(Val, Ty, Offset);
6816
6817 case APValue::ComplexInt:
6818 case APValue::ComplexFloat:
6819 case APValue::Vector:
6820 case APValue::FixedPoint:
6821 // FIXME: We should support these.
6822
6823 case APValue::Union:
6824 case APValue::MemberPointer:
6825 case APValue::AddrLabelDiff: {
6826 Info.FFDiag(BCE->getBeginLoc(),
6827 diag::note_constexpr_bit_cast_unsupported_type)
6828 << Ty;
6829 return false;
6830 }
6831
6832 case APValue::LValue:
6833 llvm_unreachable("LValue subobject in bit_cast?");
6834 }
6835 llvm_unreachable("Unhandled APValue::ValueKind");
6836 }
6837
6838 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) {
6839 const RecordDecl *RD = Ty->getAsRecordDecl();
6840 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
6841
6842 // Visit the base classes.
6843 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
6844 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
6845 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
6846 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
6847
6848 if (!visitRecord(Val.getStructBase(I), BS.getType(),
6849 Layout.getBaseClassOffset(BaseDecl) + Offset))
6850 return false;
6851 }
6852 }
6853
6854 // Visit the fields.
6855 unsigned FieldIdx = 0;
6856 for (FieldDecl *FD : RD->fields()) {
6857 if (FD->isBitField()) {
6858 Info.FFDiag(BCE->getBeginLoc(),
6859 diag::note_constexpr_bit_cast_unsupported_bitfield);
6860 return false;
6861 }
6862
6863 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
6864
6865 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 &&
6866 "only bit-fields can have sub-char alignment");
6867 CharUnits FieldOffset =
6868 Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset;
6869 QualType FieldTy = FD->getType();
6870 if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset))
6871 return false;
6872 ++FieldIdx;
6873 }
6874
6875 return true;
6876 }
6877
6878 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) {
6879 const auto *CAT =
6880 dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe());
6881 if (!CAT)
6882 return false;
6883
6884 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType());
6885 unsigned NumInitializedElts = Val.getArrayInitializedElts();
6886 unsigned ArraySize = Val.getArraySize();
6887 // First, initialize the initialized elements.
6888 for (unsigned I = 0; I != NumInitializedElts; ++I) {
6889 const APValue &SubObj = Val.getArrayInitializedElt(I);
6890 if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth))
6891 return false;
6892 }
6893
6894 // Next, initialize the rest of the array using the filler.
6895 if (Val.hasArrayFiller()) {
6896 const APValue &Filler = Val.getArrayFiller();
6897 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) {
6898 if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth))
6899 return false;
6900 }
6901 }
6902
6903 return true;
6904 }
6905
6906 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) {
6907 APSInt AdjustedVal = Val;
6908 unsigned Width = AdjustedVal.getBitWidth();
6909 if (Ty->isBooleanType()) {
6910 Width = Info.Ctx.getTypeSize(Ty);
6911 AdjustedVal = AdjustedVal.extend(Width);
6912 }
6913
6914 SmallVector<unsigned char, 8> Bytes(Width / 8);
6915 llvm::StoreIntToMemory(AdjustedVal, &*Bytes.begin(), Width / 8);
6916 Buffer.writeObject(Offset, Bytes);
6917 return true;
6918 }
6919
6920 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) {
6921 APSInt AsInt(Val.bitcastToAPInt());
6922 return visitInt(AsInt, Ty, Offset);
6923 }
6924
6925public:
6926 static Optional<BitCastBuffer> convert(EvalInfo &Info, const APValue &Src,
6927 const CastExpr *BCE) {
6928 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType());
6929 APValueToBufferConverter Converter(Info, DstSize, BCE);
6930 if (!Converter.visit(Src, BCE->getSubExpr()->getType()))
6931 return None;
6932 return Converter.Buffer;
6933 }
6934};
6935
6936/// Write an BitCastBuffer into an APValue.
6937class BufferToAPValueConverter {
6938 EvalInfo &Info;
6939 const BitCastBuffer &Buffer;
6940 const CastExpr *BCE;
6941
6942 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer,
6943 const CastExpr *BCE)
6944 : Info(Info), Buffer(Buffer), BCE(BCE) {}
6945
6946 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast
6947 // with an invalid type, so anything left is a deficiency on our part (FIXME).
6948 // Ideally this will be unreachable.
6949 llvm::NoneType unsupportedType(QualType Ty) {
6950 Info.FFDiag(BCE->getBeginLoc(),
6951 diag::note_constexpr_bit_cast_unsupported_type)
6952 << Ty;
6953 return None;
6954 }
6955
6956 llvm::NoneType unrepresentableValue(QualType Ty, const APSInt &Val) {
6957 Info.FFDiag(BCE->getBeginLoc(),
6958 diag::note_constexpr_bit_cast_unrepresentable_value)
6959 << Ty << Val.toString(/*Radix=*/10);
6960 return None;
6961 }
6962
6963 Optional<APValue> visit(const BuiltinType *T, CharUnits Offset,
6964 const EnumType *EnumSugar = nullptr) {
6965 if (T->isNullPtrType()) {
6966 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0));
6967 return APValue((Expr *)nullptr,
6968 /*Offset=*/CharUnits::fromQuantity(NullValue),
6969 APValue::NoLValuePath{}, /*IsNullPtr=*/true);
6970 }
6971
6972 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T);
6973
6974 // Work around floating point types that contain unused padding bytes. This
6975 // is really just `long double` on x86, which is the only fundamental type
6976 // with padding bytes.
6977 if (T->isRealFloatingType()) {
6978 const llvm::fltSemantics &Semantics =
6979 Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
6980 unsigned NumBits = llvm::APFloatBase::getSizeInBits(Semantics);
6981 assert(NumBits % 8 == 0);
6982 CharUnits NumBytes = CharUnits::fromQuantity(NumBits / 8);
6983 if (NumBytes != SizeOf)
6984 SizeOf = NumBytes;
6985 }
6986
6987 SmallVector<uint8_t, 8> Bytes;
6988 if (!Buffer.readObject(Offset, SizeOf, Bytes)) {
6989 // If this is std::byte or unsigned char, then its okay to store an
6990 // indeterminate value.
6991 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType();
6992 bool IsUChar =
6993 !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) ||
6994 T->isSpecificBuiltinType(BuiltinType::Char_U));
6995 if (!IsStdByte && !IsUChar) {
6996 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0);
6997 Info.FFDiag(BCE->getExprLoc(),
6998 diag::note_constexpr_bit_cast_indet_dest)
6999 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned;
7000 return None;
7001 }
7002
7003 return APValue::IndeterminateValue();
7004 }
7005
7006 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true);
7007 llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size());
7008
7009 if (T->isIntegralOrEnumerationType()) {
7010 Val.setIsSigned(T->isSignedIntegerOrEnumerationType());
7011
7012 unsigned IntWidth = Info.Ctx.getIntWidth(QualType(T, 0));
7013 if (IntWidth != Val.getBitWidth()) {
7014 APSInt Truncated = Val.trunc(IntWidth);
7015 if (Truncated.extend(Val.getBitWidth()) != Val)
7016 return unrepresentableValue(QualType(T, 0), Val);
7017 Val = Truncated;
7018 }
7019
7020 return APValue(Val);
7021 }
7022
7023 if (T->isRealFloatingType()) {
7024 const llvm::fltSemantics &Semantics =
7025 Info.Ctx.getFloatTypeSemantics(QualType(T, 0));
7026 return APValue(APFloat(Semantics, Val));
7027 }
7028
7029 return unsupportedType(QualType(T, 0));
7030 }
7031
7032 Optional<APValue> visit(const RecordType *RTy, CharUnits Offset) {
7033 const RecordDecl *RD = RTy->getAsRecordDecl();
7034 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
7035
7036 unsigned NumBases = 0;
7037 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
7038 NumBases = CXXRD->getNumBases();
7039
7040 APValue ResultVal(APValue::UninitStruct(), NumBases,
7041 std::distance(RD->field_begin(), RD->field_end()));
7042
7043 // Visit the base classes.
7044 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
7045 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) {
7046 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I];
7047 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
7048 if (BaseDecl->isEmpty() ||
7049 Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero())
7050 continue;
7051
7052 Optional<APValue> SubObj = visitType(
7053 BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset);
7054 if (!SubObj)
7055 return None;
7056 ResultVal.getStructBase(I) = *SubObj;
7057 }
7058 }
7059
7060 // Visit the fields.
7061 unsigned FieldIdx = 0;
7062 for (FieldDecl *FD : RD->fields()) {
7063 // FIXME: We don't currently support bit-fields. A lot of the logic for
7064 // this is in CodeGen, so we need to factor it around.
7065 if (FD->isBitField()) {
7066 Info.FFDiag(BCE->getBeginLoc(),
7067 diag::note_constexpr_bit_cast_unsupported_bitfield);
7068 return None;
7069 }
7070
7071 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx);
7072 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0);
7073
7074 CharUnits FieldOffset =
7075 CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) +
7076 Offset;
7077 QualType FieldTy = FD->getType();
7078 Optional<APValue> SubObj = visitType(FieldTy, FieldOffset);
7079 if (!SubObj)
7080 return None;
7081 ResultVal.getStructField(FieldIdx) = *SubObj;
7082 ++FieldIdx;
7083 }
7084
7085 return ResultVal;
7086 }
7087
7088 Optional<APValue> visit(const EnumType *Ty, CharUnits Offset) {
7089 QualType RepresentationType = Ty->getDecl()->getIntegerType();
7090 assert(!RepresentationType.isNull() &&
7091 "enum forward decl should be caught by Sema");
7092 const auto *AsBuiltin =
7093 RepresentationType.getCanonicalType()->castAs<BuiltinType>();
7094 // Recurse into the underlying type. Treat std::byte transparently as
7095 // unsigned char.
7096 return visit(AsBuiltin, Offset, /*EnumTy=*/Ty);
7097 }
7098
7099 Optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) {
7100 size_t Size = Ty->getSize().getLimitedValue();
7101 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType());
7102
7103 APValue ArrayValue(APValue::UninitArray(), Size, Size);
7104 for (size_t I = 0; I != Size; ++I) {
7105 Optional<APValue> ElementValue =
7106 visitType(Ty->getElementType(), Offset + I * ElementWidth);
7107 if (!ElementValue)
7108 return None;
7109 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue);
7110 }
7111
7112 return ArrayValue;
7113 }
7114
7115 Optional<APValue> visit(const Type *Ty, CharUnits Offset) {
7116 return unsupportedType(QualType(Ty, 0));
7117 }
7118
7119 Optional<APValue> visitType(QualType Ty, CharUnits Offset) {
7120 QualType Can = Ty.getCanonicalType();
7121
7122 switch (Can->getTypeClass()) {
7123#define TYPE(Class, Base) \
7124 case Type::Class: \
7125 return visit(cast<Class##Type>(Can.getTypePtr()), Offset);
7126#define ABSTRACT_TYPE(Class, Base)
7127#define NON_CANONICAL_TYPE(Class, Base) \
7128 case Type::Class: \
7129 llvm_unreachable("non-canonical type should be impossible!");
7130#define DEPENDENT_TYPE(Class, Base) \
7131 case Type::Class: \
7132 llvm_unreachable( \
7133 "dependent types aren't supported in the constant evaluator!");
7134#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \
7135 case Type::Class: \
7136 llvm_unreachable("either dependent or not canonical!");
7137#include "clang/AST/TypeNodes.inc"
7138 }
7139 llvm_unreachable("Unhandled Type::TypeClass");
7140 }
7141
7142public:
7143 // Pull out a full value of type DstType.
7144 static Optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer,
7145 const CastExpr *BCE) {
7146 BufferToAPValueConverter Converter(Info, Buffer, BCE);
7147 return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0));
7148 }
7149};
7150
7151static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
7152 QualType Ty, EvalInfo *Info,
7153 const ASTContext &Ctx,
7154 bool CheckingDest) {
7155 Ty = Ty.getCanonicalType();
7156
7157 auto diag = [&](int Reason) {
7158 if (Info)
7159 Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type)
7160 << CheckingDest << (Reason == 4) << Reason;
7161 return false;
7162 };
7163 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) {
7164 if (Info)
7165 Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype)
7166 << NoteTy << Construct << Ty;
7167 return false;
7168 };
7169
7170 if (Ty->isUnionType())
7171 return diag(0);
7172 if (Ty->isPointerType())
7173 return diag(1);
7174 if (Ty->isMemberPointerType())
7175 return diag(2);
7176 if (Ty.isVolatileQualified())
7177 return diag(3);
7178
7179 if (RecordDecl *Record = Ty->getAsRecordDecl()) {
7180 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) {
7181 for (CXXBaseSpecifier &BS : CXXRD->bases())
7182 if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx,
7183 CheckingDest))
7184 return note(1, BS.getType(), BS.getBeginLoc());
7185 }
7186 for (FieldDecl *FD : Record->fields()) {
7187 if (FD->getType()->isReferenceType())
7188 return diag(4);
7189 if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx,
7190 CheckingDest))
7191 return note(0, FD->getType(), FD->getBeginLoc());
7192 }
7193 }
7194
7195 if (Ty->isArrayType() &&
7196 !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty),
7197 Info, Ctx, CheckingDest))
7198 return false;
7199
7200 return true;
7201}
7202
7203static bool checkBitCastConstexprEligibility(EvalInfo *Info,
7204 const ASTContext &Ctx,
7205 const CastExpr *BCE) {
7206 bool DestOK = checkBitCastConstexprEligibilityType(
7207 BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true);
7208 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType(
7209 BCE->getBeginLoc(),
7210 BCE->getSubExpr()->getType(), Info, Ctx, false);
7211 return SourceOK;
7212}
7213
7214static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue,
7215 APValue &SourceValue,
7216 const CastExpr *BCE) {
7217 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 &&
7218 "no host or target supports non 8-bit chars");
7219 assert(SourceValue.isLValue() &&
7220 "LValueToRValueBitcast requires an lvalue operand!");
7221
7222 if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE))
7223 return false;
7224
7225 LValue SourceLValue;
7226 APValue SourceRValue;
7227 SourceLValue.setFrom(Info.Ctx, SourceValue);
7228 if (!handleLValueToRValueConversion(
7229 Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue,
7230 SourceRValue, /*WantObjectRepresentation=*/true))
7231 return false;
7232
7233 // Read out SourceValue into a char buffer.
7234 Optional<BitCastBuffer> Buffer =
7235 APValueToBufferConverter::convert(Info, SourceRValue, BCE);
7236 if (!Buffer)
7237 return false;
7238
7239 // Write out the buffer into a new APValue.
7240 Optional<APValue> MaybeDestValue =
7241 BufferToAPValueConverter::convert(Info, *Buffer, BCE);
7242 if (!MaybeDestValue)
7243 return false;
7244
7245 DestValue = std::move(*MaybeDestValue);
7246 return true;
7247}
7248
7249template <class Derived>
7250class ExprEvaluatorBase
7251 : public ConstStmtVisitor<Derived, bool> {
7252private:
7253 Derived &getDerived() { return static_cast<Derived&>(*this); }
7254 bool DerivedSuccess(const APValue &V, const Expr *E) {
7255 return getDerived().Success(V, E);
7256 }
7257 bool DerivedZeroInitialization(const Expr *E) {
7258 return getDerived().ZeroInitialization(E);
7259 }
7260
7261 // Check whether a conditional operator with a non-constant condition is a
7262 // potential constant expression. If neither arm is a potential constant
7263 // expression, then the conditional operator is not either.
7264 template<typename ConditionalOperator>
7265 void CheckPotentialConstantConditional(const ConditionalOperator *E) {
7266 assert(Info.checkingPotentialConstantExpression());
7267
7268 // Speculatively evaluate both arms.
7269 SmallVector<PartialDiagnosticAt, 8> Diag;
7270 {
7271 SpeculativeEvaluationRAII Speculate(Info, &Diag);
7272 StmtVisitorTy::Visit(E->getFalseExpr());
7273 if (Diag.empty())
7274 return;
7275 }
7276
7277 {
7278 SpeculativeEvaluationRAII Speculate(Info, &Diag);
7279 Diag.clear();
7280 StmtVisitorTy::Visit(E->getTrueExpr());
7281 if (Diag.empty())
7282 return;
7283 }
7284
7285 Error(E, diag::note_constexpr_conditional_never_const);
7286 }
7287
7288
7289 template<typename ConditionalOperator>
7290 bool HandleConditionalOperator(const ConditionalOperator *E) {
7291 bool BoolResult;
7292 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) {
7293 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) {
7294 CheckPotentialConstantConditional(E);
7295 return false;
7296 }
7297 if (Info.noteFailure()) {
7298 StmtVisitorTy::Visit(E->getTrueExpr());
7299 StmtVisitorTy::Visit(E->getFalseExpr());
7300 }
7301 return false;
7302 }
7303
7304 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr();
7305 return StmtVisitorTy::Visit(EvalExpr);
7306 }
7307
7308protected:
7309 EvalInfo &Info;
7310 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy;
7311 typedef ExprEvaluatorBase ExprEvaluatorBaseTy;
7312
7313 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
7314 return Info.CCEDiag(E, D);
7315 }
7316
7317 bool ZeroInitialization(const Expr *E) { return Error(E); }
7318
7319public:
7320 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {}
7321
7322 EvalInfo &getEvalInfo() { return Info; }
7323
7324 /// Report an evaluation error. This should only be called when an error is
7325 /// first discovered. When propagating an error, just return false.
7326 bool Error(const Expr *E, diag::kind D) {
7327 Info.FFDiag(E, D);
7328 return false;
7329 }
7330 bool Error(const Expr *E) {
7331 return Error(E, diag::note_invalid_subexpr_in_const_expr);
7332 }
7333
7334 bool VisitStmt(const Stmt *) {
7335 llvm_unreachable("Expression evaluator should not be called on stmts");
7336 }
7337 bool VisitExpr(const Expr *E) {
7338 return Error(E);
7339 }
7340
7341 bool VisitConstantExpr(const ConstantExpr *E) {
7342 if (E->hasAPValueResult())
7343 return DerivedSuccess(E->getAPValueResult(), E);
7344
7345 return StmtVisitorTy::Visit(E->getSubExpr());
7346 }
7347
7348 bool VisitParenExpr(const ParenExpr *E)
7349 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7350 bool VisitUnaryExtension(const UnaryOperator *E)
7351 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7352 bool VisitUnaryPlus(const UnaryOperator *E)
7353 { return StmtVisitorTy::Visit(E->getSubExpr()); }
7354 bool VisitChooseExpr(const ChooseExpr *E)
7355 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); }
7356 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E)
7357 { return StmtVisitorTy::Visit(E->getResultExpr()); }
7358 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E)
7359 { return StmtVisitorTy::Visit(E->getReplacement()); }
7360 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) {
7361 TempVersionRAII RAII(*Info.CurrentCall);
7362 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7363 return StmtVisitorTy::Visit(E->getExpr());
7364 }
7365 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) {
7366 TempVersionRAII RAII(*Info.CurrentCall);
7367 // The initializer may not have been parsed yet, or might be erroneous.
7368 if (!E->getExpr())
7369 return Error(E);
7370 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope);
7371 return StmtVisitorTy::Visit(E->getExpr());
7372 }
7373
7374 bool VisitExprWithCleanups(const ExprWithCleanups *E) {
7375 FullExpressionRAII Scope(Info);
7376 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy();
7377 }
7378
7379 // Temporaries are registered when created, so we don't care about
7380 // CXXBindTemporaryExpr.
7381 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
7382 return StmtVisitorTy::Visit(E->getSubExpr());
7383 }
7384
7385 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) {
7386 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0;
7387 return static_cast<Derived*>(this)->VisitCastExpr(E);
7388 }
7389 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) {
7390 if (!Info.Ctx.getLangOpts().CPlusPlus20)
7391 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1;
7392 return static_cast<Derived*>(this)->VisitCastExpr(E);
7393 }
7394 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) {
7395 return static_cast<Derived*>(this)->VisitCastExpr(E);
7396 }
7397
7398 bool VisitBinaryOperator(const BinaryOperator *E) {
7399 switch (E->getOpcode()) {
7400 default:
7401 return Error(E);
7402
7403 case BO_Comma:
7404 VisitIgnoredValue(E->getLHS());
7405 return StmtVisitorTy::Visit(E->getRHS());
7406
7407 case BO_PtrMemD:
7408 case BO_PtrMemI: {
7409 LValue Obj;
7410 if (!HandleMemberPointerAccess(Info, E, Obj))
7411 return false;
7412 APValue Result;
7413 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result))
7414 return false;
7415 return DerivedSuccess(Result, E);
7416 }
7417 }
7418 }
7419
7420 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) {
7421 return StmtVisitorTy::Visit(E->getSemanticForm());
7422 }
7423
7424 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) {
7425 // Evaluate and cache the common expression. We treat it as a temporary,
7426 // even though it's not quite the same thing.
7427 LValue CommonLV;
7428 if (!Evaluate(Info.CurrentCall->createTemporary(
7429 E->getOpaqueValue(),
7430 getStorageType(Info.Ctx, E->getOpaqueValue()),
7431 ScopeKind::FullExpression, CommonLV),
7432 Info, E->getCommon()))
7433 return false;
7434
7435 return HandleConditionalOperator(E);
7436 }
7437
7438 bool VisitConditionalOperator(const ConditionalOperator *E) {
7439 bool IsBcpCall = false;
7440 // If the condition (ignoring parens) is a __builtin_constant_p call,
7441 // the result is a constant expression if it can be folded without
7442 // side-effects. This is an important GNU extension. See GCC PR38377
7443 // for discussion.
7444 if (const CallExpr *CallCE =
7445 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts()))
7446 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
7447 IsBcpCall = true;
7448
7449 // Always assume __builtin_constant_p(...) ? ... : ... is a potential
7450 // constant expression; we can't check whether it's potentially foldable.
7451 // FIXME: We should instead treat __builtin_constant_p as non-constant if
7452 // it would return 'false' in this mode.
7453 if (Info.checkingPotentialConstantExpression() && IsBcpCall)
7454 return false;
7455
7456 FoldConstant Fold(Info, IsBcpCall);
7457 if (!HandleConditionalOperator(E)) {
7458 Fold.keepDiagnostics();
7459 return false;
7460 }
7461
7462 return true;
7463 }
7464
7465 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
7466 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E))
7467 return DerivedSuccess(*Value, E);
7468
7469 const Expr *Source = E->getSourceExpr();
7470 if (!Source)
7471 return Error(E);
7472 if (Source == E) { // sanity checking.
7473 assert(0 && "OpaqueValueExpr recursively refers to itself");
7474 return Error(E);
7475 }
7476 return StmtVisitorTy::Visit(Source);
7477 }
7478
7479 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
7480 for (const Expr *SemE : E->semantics()) {
7481 if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
7482 // FIXME: We can't handle the case where an OpaqueValueExpr is also the
7483 // result expression: there could be two different LValues that would
7484 // refer to the same object in that case, and we can't model that.
7485 if (SemE == E->getResultExpr())
7486 return Error(E);
7487
7488 // Unique OVEs get evaluated if and when we encounter them when
7489 // emitting the rest of the semantic form, rather than eagerly.
7490 if (OVE->isUnique())
7491 continue;
7492
7493 LValue LV;
7494 if (!Evaluate(Info.CurrentCall->createTemporary(
7495 OVE, getStorageType(Info.Ctx, OVE),
7496 ScopeKind::FullExpression, LV),
7497 Info, OVE->getSourceExpr()))
7498 return false;
7499 } else if (SemE == E->getResultExpr()) {
7500 if (!StmtVisitorTy::Visit(SemE))
7501 return false;
7502 } else {
7503 if (!EvaluateIgnoredValue(Info, SemE))
7504 return false;
7505 }
7506 }
7507 return true;
7508 }
7509
7510 bool VisitCallExpr(const CallExpr *E) {
7511 APValue Result;
7512 if (!handleCallExpr(E, Result, nullptr))
7513 return false;
7514 return DerivedSuccess(Result, E);
7515 }
7516
7517 bool handleCallExpr(const CallExpr *E, APValue &Result,
7518 const LValue *ResultSlot) {
7519 CallScopeRAII CallScope(Info);
7520
7521 const Expr *Callee = E->getCallee()->IgnoreParens();
7522 QualType CalleeType = Callee->getType();
7523
7524 const FunctionDecl *FD = nullptr;
7525 LValue *This = nullptr, ThisVal;
7526 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
7527 bool HasQualifier = false;
7528
7529 CallRef Call;
7530
7531 // Extract function decl and 'this' pointer from the callee.
7532 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
7533 const CXXMethodDecl *Member = nullptr;
7534 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) {
7535 // Explicit bound member calls, such as x.f() or p->g();
7536 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal))
7537 return false;
7538 Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
7539 if (!Member)
7540 return Error(Callee);
7541 This = &ThisVal;
7542 HasQualifier = ME->hasQualifier();
7543 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) {
7544 // Indirect bound member calls ('.*' or '->*').
7545 const ValueDecl *D =
7546 HandleMemberPointerAccess(Info, BE, ThisVal, false);
7547 if (!D)
7548 return false;
7549 Member = dyn_cast<CXXMethodDecl>(D);
7550 if (!Member)
7551 return Error(Callee);
7552 This = &ThisVal;
7553 } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) {
7554 if (!Info.getLangOpts().CPlusPlus20)
7555 Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor);
7556 return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) &&
7557 HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType());
7558 } else
7559 return Error(Callee);
7560 FD = Member;
7561 } else if (CalleeType->isFunctionPointerType()) {
7562 LValue CalleeLV;
7563 if (!EvaluatePointer(Callee, CalleeLV, Info))
7564 return false;
7565
7566 if (!CalleeLV.getLValueOffset().isZero())
7567 return Error(Callee);
7568 FD = dyn_cast_or_null<FunctionDecl>(
7569 CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>());
7570 if (!FD)
7571 return Error(Callee);
7572 // Don't call function pointers which have been cast to some other type.
7573 // Per DR (no number yet), the caller and callee can differ in noexcept.
7574 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
7575 CalleeType->getPointeeType(), FD->getType())) {
7576 return Error(E);
7577 }
7578
7579 // For an (overloaded) assignment expression, evaluate the RHS before the
7580 // LHS.
7581 auto *OCE = dyn_cast<CXXOperatorCallExpr>(E);
7582 if (OCE && OCE->isAssignmentOp()) {
7583 assert(Args.size() == 2 && "wrong number of arguments in assignment");
7584 Call = Info.CurrentCall->createCall(FD);
7585 if (!EvaluateArgs(isa<CXXMethodDecl>(FD) ? Args.slice(1) : Args, Call,
7586 Info, FD, /*RightToLeft=*/true))
7587 return false;
7588 }
7589
7590 // Overloaded operator calls to member functions are represented as normal
7591 // calls with '*this' as the first argument.
7592 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
7593 if (MD && !MD->isStatic()) {
7594 // FIXME: When selecting an implicit conversion for an overloaded
7595 // operator delete, we sometimes try to evaluate calls to conversion
7596 // operators without a 'this' parameter!
7597 if (Args.empty())
7598 return Error(E);
7599
7600 if (!EvaluateObjectArgument(Info, Args[0], ThisVal))
7601 return false;
7602 This = &ThisVal;
7603 Args = Args.slice(1);
7604 } else if (MD && MD->isLambdaStaticInvoker()) {
7605 // Map the static invoker for the lambda back to the call operator.
7606 // Conveniently, we don't have to slice out the 'this' argument (as is
7607 // being done for the non-static case), since a static member function
7608 // doesn't have an implicit argument passed in.
7609 const CXXRecordDecl *ClosureClass = MD->getParent();
7610 assert(
7611 ClosureClass->captures_begin() == ClosureClass->captures_end() &&
7612 "Number of captures must be zero for conversion to function-ptr");
7613
7614 const CXXMethodDecl *LambdaCallOp =
7615 ClosureClass->getLambdaCallOperator();
7616
7617 // Set 'FD', the function that will be called below, to the call
7618 // operator. If the closure object represents a generic lambda, find
7619 // the corresponding specialization of the call operator.
7620
7621 if (ClosureClass->isGenericLambda()) {
7622 assert(MD->isFunctionTemplateSpecialization() &&
7623 "A generic lambda's static-invoker function must be a "
7624 "template specialization");
7625 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
7626 FunctionTemplateDecl *CallOpTemplate =
7627 LambdaCallOp->getDescribedFunctionTemplate();
7628 void *InsertPos = nullptr;
7629 FunctionDecl *CorrespondingCallOpSpecialization =
7630 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
7631 assert(CorrespondingCallOpSpecialization &&
7632 "We must always have a function call operator specialization "
7633 "that corresponds to our static invoker specialization");
7634 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
7635 } else
7636 FD = LambdaCallOp;
7637 } else if (FD->isReplaceableGlobalAllocationFunction()) {
7638 if (FD->getDeclName().getCXXOverloadedOperator() == OO_New ||
7639 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) {
7640 LValue Ptr;
7641 if (!HandleOperatorNewCall(Info, E, Ptr))
7642 return false;
7643 Ptr.moveInto(Result);
7644 return CallScope.destroy();
7645 } else {
7646 return HandleOperatorDeleteCall(Info, E) && CallScope.destroy();
7647 }
7648 }
7649 } else
7650 return Error(E);
7651
7652 // Evaluate the arguments now if we've not already done so.
7653 if (!Call) {
7654 Call = Info.CurrentCall->createCall(FD);
7655 if (!EvaluateArgs(Args, Call, Info, FD))
7656 return false;
7657 }
7658
7659 SmallVector<QualType, 4> CovariantAdjustmentPath;
7660 if (This) {
7661 auto *NamedMember = dyn_cast<CXXMethodDecl>(FD);
7662 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) {
7663 // Perform virtual dispatch, if necessary.
7664 FD = HandleVirtualDispatch(Info, E, *This, NamedMember,
7665 CovariantAdjustmentPath);
7666 if (!FD)
7667 return false;
7668 } else {
7669 // Check that the 'this' pointer points to an object of the right type.
7670 // FIXME: If this is an assignment operator call, we may need to change
7671 // the active union member before we check this.
7672 if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember))
7673 return false;
7674 }
7675 }
7676
7677 // Destructor calls are different enough that they have their own codepath.
7678 if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) {
7679 assert(This && "no 'this' pointer for destructor call");
7680 return HandleDestruction(Info, E, *This,
7681 Info.Ctx.getRecordType(DD->getParent())) &&
7682 CallScope.destroy();
7683 }
7684
7685 const FunctionDecl *Definition = nullptr;
7686 Stmt *Body = FD->getBody(Definition);
7687
7688 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
7689 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Call,
7690 Body, Info, Result, ResultSlot))
7691 return false;
7692
7693 if (!CovariantAdjustmentPath.empty() &&
7694 !HandleCovariantReturnAdjustment(Info, E, Result,
7695 CovariantAdjustmentPath))
7696 return false;
7697
7698 return CallScope.destroy();
7699 }
7700
7701 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
7702 return StmtVisitorTy::Visit(E->getInitializer());
7703 }
7704 bool VisitInitListExpr(const InitListExpr *E) {
7705 if (E->getNumInits() == 0)
7706 return DerivedZeroInitialization(E);
7707 if (E->getNumInits() == 1)
7708 return StmtVisitorTy::Visit(E->getInit(0));
7709 return Error(E);
7710 }
7711 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
7712 return DerivedZeroInitialization(E);
7713 }
7714 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) {
7715 return DerivedZeroInitialization(E);
7716 }
7717 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) {
7718 return DerivedZeroInitialization(E);
7719 }
7720
7721 /// A member expression where the object is a prvalue is itself a prvalue.
7722 bool VisitMemberExpr(const MemberExpr *E) {
7723 assert(!Info.Ctx.getLangOpts().CPlusPlus11 &&
7724 "missing temporary materialization conversion");
7725 assert(!E->isArrow() && "missing call to bound member function?");
7726
7727 APValue Val;
7728 if (!Evaluate(Val, Info, E->getBase()))
7729 return false;
7730
7731 QualType BaseTy = E->getBase()->getType();
7732
7733 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl());
7734 if (!FD) return Error(E);
7735 assert(!FD->getType()->isReferenceType() && "prvalue reference?");
7736 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
7737 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
7738
7739 // Note: there is no lvalue base here. But this case should only ever
7740 // happen in C or in C++98, where we cannot be evaluating a constexpr
7741 // constructor, which is the only case the base matters.
7742 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy);
7743 SubobjectDesignator Designator(BaseTy);
7744 Designator.addDeclUnchecked(FD);
7745
7746 APValue Result;
7747 return extractSubobject(Info, E, Obj, Designator, Result) &&
7748 DerivedSuccess(Result, E);
7749 }
7750
7751 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) {
7752 APValue Val;
7753 if (!Evaluate(Val, Info, E->getBase()))
7754 return false;
7755
7756 if (Val.isVector()) {
7757 SmallVector<uint32_t, 4> Indices;
7758 E->getEncodedElementAccess(Indices);
7759 if (Indices.size() == 1) {
7760 // Return scalar.
7761 return DerivedSuccess(Val.getVectorElt(Indices[0]), E);
7762 } else {
7763 // Construct new APValue vector.
7764 SmallVector<APValue, 4> Elts;
7765 for (unsigned I = 0; I < Indices.size(); ++I) {
7766 Elts.push_back(Val.getVectorElt(Indices[I]));
7767 }
7768 APValue VecResult(Elts.data(), Indices.size());
7769 return DerivedSuccess(VecResult, E);
7770 }
7771 }
7772
7773 return false;
7774 }
7775
7776 bool VisitCastExpr(const CastExpr *E) {
7777 switch (E->getCastKind()) {
7778 default:
7779 break;
7780
7781 case CK_AtomicToNonAtomic: {
7782 APValue AtomicVal;
7783 // This does not need to be done in place even for class/array types:
7784 // atomic-to-non-atomic conversion implies copying the object
7785 // representation.
7786 if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
7787 return false;
7788 return DerivedSuccess(AtomicVal, E);
7789 }
7790
7791 case CK_NoOp:
7792 case CK_UserDefinedConversion:
7793 return StmtVisitorTy::Visit(E->getSubExpr());
7794
7795 case CK_LValueToRValue: {
7796 LValue LVal;
7797 if (!EvaluateLValue(E->getSubExpr(), LVal, Info))
7798 return false;
7799 APValue RVal;
7800 // Note, we use the subexpression's type in order to retain cv-qualifiers.
7801 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
7802 LVal, RVal))
7803 return false;
7804 return DerivedSuccess(RVal, E);
7805 }
7806 case CK_LValueToRValueBitCast: {
7807 APValue DestValue, SourceValue;
7808 if (!Evaluate(SourceValue, Info, E->getSubExpr()))
7809 return false;
7810 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E))
7811 return false;
7812 return DerivedSuccess(DestValue, E);
7813 }
7814
7815 case CK_AddressSpaceConversion: {
7816 APValue Value;
7817 if (!Evaluate(Value, Info, E->getSubExpr()))
7818 return false;
7819 return DerivedSuccess(Value, E);
7820 }
7821 }
7822
7823 return Error(E);
7824 }
7825
7826 bool VisitUnaryPostInc(const UnaryOperator *UO) {
7827 return VisitUnaryPostIncDec(UO);
7828 }
7829 bool VisitUnaryPostDec(const UnaryOperator *UO) {
7830 return VisitUnaryPostIncDec(UO);
7831 }
7832 bool VisitUnaryPostIncDec(const UnaryOperator *UO) {
7833 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
7834 return Error(UO);
7835
7836 LValue LVal;
7837 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info))
7838 return false;
7839 APValue RVal;
7840 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(),
7841 UO->isIncrementOp(), &RVal))
7842 return false;
7843 return DerivedSuccess(RVal, UO);
7844 }
7845
7846 bool VisitStmtExpr(const StmtExpr *E) {
7847 // We will have checked the full-expressions inside the statement expression
7848 // when they were completed, and don't need to check them again now.
7849 if (Info.checkingForUndefinedBehavior())
7850 return Error(E);
7851
7852 const CompoundStmt *CS = E->getSubStmt();
7853 if (CS->body_empty())
7854 return true;
7855
7856 BlockScopeRAII Scope(Info);
7857 for (CompoundStmt::const_body_iterator BI = CS->body_begin(),
7858 BE = CS->body_end();
7859 /**/; ++BI) {
7860 if (BI + 1 == BE) {
7861 const Expr *FinalExpr = dyn_cast<Expr>(*BI);
7862 if (!FinalExpr) {
7863 Info.FFDiag((*BI)->getBeginLoc(),
7864 diag::note_constexpr_stmt_expr_unsupported);
7865 return false;
7866 }
7867 return this->Visit(FinalExpr) && Scope.destroy();
7868 }
7869
7870 APValue ReturnValue;
7871 StmtResult Result = { ReturnValue, nullptr };
7872 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI);
7873 if (ESR != ESR_Succeeded) {
7874 // FIXME: If the statement-expression terminated due to 'return',
7875 // 'break', or 'continue', it would be nice to propagate that to
7876 // the outer statement evaluation rather than bailing out.
7877 if (ESR != ESR_Failed)
7878 Info.FFDiag((*BI)->getBeginLoc(),
7879 diag::note_constexpr_stmt_expr_unsupported);
7880 return false;
7881 }
7882 }
7883
7884 llvm_unreachable("Return from function from the loop above.");
7885 }
7886
7887 /// Visit a value which is evaluated, but whose value is ignored.
7888 void VisitIgnoredValue(const Expr *E) {
7889 EvaluateIgnoredValue(Info, E);
7890 }
7891
7892 /// Potentially visit a MemberExpr's base expression.
7893 void VisitIgnoredBaseExpression(const Expr *E) {
7894 // While MSVC doesn't evaluate the base expression, it does diagnose the
7895 // presence of side-effecting behavior.
7896 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
7897 return;
7898 VisitIgnoredValue(E);
7899 }
7900};
7901
7902} // namespace
7903
7904//===----------------------------------------------------------------------===//
7905// Common base class for lvalue and temporary evaluation.
7906//===----------------------------------------------------------------------===//
7907namespace {
7908template<class Derived>
7909class LValueExprEvaluatorBase
7910 : public ExprEvaluatorBase<Derived> {
7911protected:
7912 LValue &Result;
7913 bool InvalidBaseOK;
7914 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy;
7915 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy;
7916
7917 bool Success(APValue::LValueBase B) {
7918 Result.set(B);
7919 return true;
7920 }
7921
7922 bool evaluatePointer(const Expr *E, LValue &Result) {
7923 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK);
7924 }
7925
7926public:
7927 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK)
7928 : ExprEvaluatorBaseTy(Info), Result(Result),
7929 InvalidBaseOK(InvalidBaseOK) {}
7930
7931 bool Success(const APValue &V, const Expr *E) {
7932 Result.setFrom(this->Info.Ctx, V);
7933 return true;
7934 }
7935
7936 bool VisitMemberExpr(const MemberExpr *E) {
7937 // Handle non-static data members.
7938 QualType BaseTy;
7939 bool EvalOK;
7940 if (E->isArrow()) {
7941 EvalOK = evaluatePointer(E->getBase(), Result);
7942 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType();
7943 } else if (E->getBase()->isRValue()) {
7944 assert(E->getBase()->getType()->isRecordType());
7945 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info);
7946 BaseTy = E->getBase()->getType();
7947 } else {
7948 EvalOK = this->Visit(E->getBase());
7949 BaseTy = E->getBase()->getType();
7950 }
7951 if (!EvalOK) {
7952 if (!InvalidBaseOK)
7953 return false;
7954 Result.setInvalid(E);
7955 return true;
7956 }
7957
7958 const ValueDecl *MD = E->getMemberDecl();
7959 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) {
7960 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() ==
7961 FD->getParent()->getCanonicalDecl() && "record / field mismatch");
7962 (void)BaseTy;
7963 if (!HandleLValueMember(this->Info, E, Result, FD))
7964 return false;
7965 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) {
7966 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD))
7967 return false;
7968 } else
7969 return this->Error(E);
7970
7971 if (MD->getType()->isReferenceType()) {
7972 APValue RefValue;
7973 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result,
7974 RefValue))
7975 return false;
7976 return Success(RefValue, E);
7977 }
7978 return true;
7979 }
7980
7981 bool VisitBinaryOperator(const BinaryOperator *E) {
7982 switch (E->getOpcode()) {
7983 default:
7984 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
7985
7986 case BO_PtrMemD:
7987 case BO_PtrMemI:
7988 return HandleMemberPointerAccess(this->Info, E, Result);
7989 }
7990 }
7991
7992 bool VisitCastExpr(const CastExpr *E) {
7993 switch (E->getCastKind()) {
7994 default:
7995 return ExprEvaluatorBaseTy::VisitCastExpr(E);
7996
7997 case CK_DerivedToBase:
7998 case CK_UncheckedDerivedToBase:
7999 if (!this->Visit(E->getSubExpr()))
8000 return false;
8001
8002 // Now figure out the necessary offset to add to the base LV to get from
8003 // the derived class to the base class.
8004 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(),
8005 Result);
8006 }
8007 }
8008};
8009}
8010
8011//===----------------------------------------------------------------------===//
8012// LValue Evaluation
8013//
8014// This is used for evaluating lvalues (in C and C++), xvalues (in C++11),
8015// function designators (in C), decl references to void objects (in C), and
8016// temporaries (if building with -Wno-address-of-temporary).
8017//
8018// LValue evaluation produces values comprising a base expression of one of the
8019// following types:
8020// - Declarations
8021// * VarDecl
8022// * FunctionDecl
8023// - Literals
8024// * CompoundLiteralExpr in C (and in global scope in C++)
8025// * StringLiteral
8026// * PredefinedExpr
8027// * ObjCStringLiteralExpr
8028// * ObjCEncodeExpr
8029// * AddrLabelExpr
8030// * BlockExpr
8031// * CallExpr for a MakeStringConstant builtin
8032// - typeid(T) expressions, as TypeInfoLValues
8033// - Locals and temporaries
8034// * MaterializeTemporaryExpr
8035// * Any Expr, with a CallIndex indicating the function in which the temporary
8036// was evaluated, for cases where the MaterializeTemporaryExpr is missing
8037// from the AST (FIXME).
8038// * A MaterializeTemporaryExpr that has static storage duration, with no
8039// CallIndex, for a lifetime-extended temporary.
8040// * The ConstantExpr that is currently being evaluated during evaluation of an
8041// immediate invocation.
8042// plus an offset in bytes.
8043//===----------------------------------------------------------------------===//
8044namespace {
8045class LValueExprEvaluator
8046 : public LValueExprEvaluatorBase<LValueExprEvaluator> {
8047public:
8048 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) :
8049 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {}
8050
8051 bool VisitVarDecl(const Expr *E, const VarDecl *VD);
8052 bool VisitUnaryPreIncDec(const UnaryOperator *UO);
8053
8054 bool VisitDeclRefExpr(const DeclRefExpr *E);
8055 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); }
8056 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E);
8057 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
8058 bool VisitMemberExpr(const MemberExpr *E);
8059 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
8060 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
8061 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
8062 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
8063 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
8064 bool VisitUnaryDeref(const UnaryOperator *E);
8065 bool VisitUnaryReal(const UnaryOperator *E);
8066 bool VisitUnaryImag(const UnaryOperator *E);
8067 bool VisitUnaryPreInc(const UnaryOperator *UO) {
8068 return VisitUnaryPreIncDec(UO);
8069 }
8070 bool VisitUnaryPreDec(const UnaryOperator *UO) {
8071 return VisitUnaryPreIncDec(UO);
8072 }
8073 bool VisitBinAssign(const BinaryOperator *BO);
8074 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO);
8075
8076 bool VisitCastExpr(const CastExpr *E) {
8077 switch (E->getCastKind()) {
8078 default:
8079 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
8080
8081 case CK_LValueBitCast:
8082 this->CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8083 if (!Visit(E->getSubExpr()))
8084 return false;
8085 Result.Designator.setInvalid();
8086 return true;
8087
8088 case CK_BaseToDerived:
8089 if (!Visit(E->getSubExpr()))
8090 return false;
8091 return HandleBaseToDerivedCast(Info, E, Result);
8092
8093 case CK_Dynamic:
8094 if (!Visit(E->getSubExpr()))
8095 return false;
8096 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
8097 }
8098 }
8099};
8100} // end anonymous namespace
8101
8102/// Evaluate an expression as an lvalue. This can be legitimately called on
8103/// expressions which are not glvalues, in three cases:
8104/// * function designators in C, and
8105/// * "extern void" objects
8106/// * @selector() expressions in Objective-C
8107static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info,
8108 bool InvalidBaseOK) {
8109 assert(!E->isValueDependent());
8110 assert(E->isGLValue() || E->getType()->isFunctionType() ||
8111 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
8112 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8113}
8114
8115bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
8116 const NamedDecl *D = E->getDecl();
8117 if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl>(D))
8118 return Success(cast<ValueDecl>(D));
8119 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
8120 return VisitVarDecl(E, VD);
8121 if (const BindingDecl *BD = dyn_cast<BindingDecl>(D))
8122 return Visit(BD->getBinding());
8123 return Error(E);
8124}
8125
8126
8127bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
8128
8129 // If we are within a lambda's call operator, check whether the 'VD' referred
8130 // to within 'E' actually represents a lambda-capture that maps to a
8131 // data-member/field within the closure object, and if so, evaluate to the
8132 // field or what the field refers to.
8133 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) &&
8134 isa<DeclRefExpr>(E) &&
8135 cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) {
8136 // We don't always have a complete capture-map when checking or inferring if
8137 // the function call operator meets the requirements of a constexpr function
8138 // - but we don't need to evaluate the captures to determine constexprness
8139 // (dcl.constexpr C++17).
8140 if (Info.checkingPotentialConstantExpression())
8141 return false;
8142
8143 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) {
8144 // Start with 'Result' referring to the complete closure object...
8145 Result = *Info.CurrentCall->This;
8146 // ... then update it to refer to the field of the closure object
8147 // that represents the capture.
8148 if (!HandleLValueMember(Info, E, Result, FD))
8149 return false;
8150 // And if the field is of reference type, update 'Result' to refer to what
8151 // the field refers to.
8152 if (FD->getType()->isReferenceType()) {
8153 APValue RVal;
8154 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result,
8155 RVal))
8156 return false;
8157 Result.setFrom(Info.Ctx, RVal);
8158 }
8159 return true;
8160 }
8161 }
8162
8163 CallStackFrame *Frame = nullptr;
8164 unsigned Version = 0;
8165 if (VD->hasLocalStorage()) {
8166 // Only if a local variable was declared in the function currently being
8167 // evaluated, do we expect to be able to find its value in the current
8168 // frame. (Otherwise it was likely declared in an enclosing context and
8169 // could either have a valid evaluatable value (for e.g. a constexpr
8170 // variable) or be ill-formed (and trigger an appropriate evaluation
8171 // diagnostic)).
8172 CallStackFrame *CurrFrame = Info.CurrentCall;
8173 if (CurrFrame->Callee && CurrFrame->Callee->Equals(VD->getDeclContext())) {
8174 // Function parameters are stored in some caller's frame. (Usually the
8175 // immediate caller, but for an inherited constructor they may be more
8176 // distant.)
8177 if (auto *PVD = dyn_cast<ParmVarDecl>(VD)) {
8178 if (CurrFrame->Arguments) {
8179 VD = CurrFrame->Arguments.getOrigParam(PVD);
8180 Frame =
8181 Info.getCallFrameAndDepth(CurrFrame->Arguments.CallIndex).first;
8182 Version = CurrFrame->Arguments.Version;
8183 }
8184 } else {
8185 Frame = CurrFrame;
8186 Version = CurrFrame->getCurrentTemporaryVersion(VD);
8187 }
8188 }
8189 }
8190
8191 if (!VD->getType()->isReferenceType()) {
8192 if (Frame) {
8193 Result.set({VD, Frame->Index, Version});
8194 return true;
8195 }
8196 return Success(VD);
8197 }
8198
8199 if (!Info.getLangOpts().CPlusPlus11) {
8200 Info.CCEDiag(E, diag::note_constexpr_ltor_non_integral, 1)
8201 << VD << VD->getType();
8202 Info.Note(VD->getLocation(), diag::note_declared_at);
8203 }
8204
8205 APValue *V;
8206 if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, V))
8207 return false;
8208 if (!V->hasValue()) {
8209 // FIXME: Is it possible for V to be indeterminate here? If so, we should
8210 // adjust the diagnostic to say that.
8211 if (!Info.checkingPotentialConstantExpression())
8212 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
8213 return false;
8214 }
8215 return Success(*V, E);
8216}
8217
8218bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
8219 const MaterializeTemporaryExpr *E) {
8220 // Walk through the expression to find the materialized temporary itself.
8221 SmallVector<const Expr *, 2> CommaLHSs;
8222 SmallVector<SubobjectAdjustment, 2> Adjustments;
8223 const Expr *Inner =
8224 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
8225
8226 // If we passed any comma operators, evaluate their LHSs.
8227 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
8228 if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
8229 return false;
8230
8231 // A materialized temporary with static storage duration can appear within the
8232 // result of a constant expression evaluation, so we need to preserve its
8233 // value for use outside this evaluation.
8234 APValue *Value;
8235 if (E->getStorageDuration() == SD_Static) {
8236 // FIXME: What about SD_Thread?
8237 Value = E->getOrCreateValue(true);
8238 *Value = APValue();
8239 Result.set(E);
8240 } else {
8241 Value = &Info.CurrentCall->createTemporary(
8242 E, E->getType(),
8243 E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression
8244 : ScopeKind::Block,
8245 Result);
8246 }
8247
8248 QualType Type = Inner->getType();
8249
8250 // Materialize the temporary itself.
8251 if (!EvaluateInPlace(*Value, Info, Result, Inner)) {
8252 *Value = APValue();
8253 return false;
8254 }
8255
8256 // Adjust our lvalue to refer to the desired subobject.
8257 for (unsigned I = Adjustments.size(); I != 0; /**/) {
8258 --I;
8259 switch (Adjustments[I].Kind) {
8260 case SubobjectAdjustment::DerivedToBaseAdjustment:
8261 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath,
8262 Type, Result))
8263 return false;
8264 Type = Adjustments[I].DerivedToBase.BasePath->getType();
8265 break;
8266
8267 case SubobjectAdjustment::FieldAdjustment:
8268 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field))
8269 return false;
8270 Type = Adjustments[I].Field->getType();
8271 break;
8272
8273 case SubobjectAdjustment::MemberPointerAdjustment:
8274 if (!HandleMemberPointerAccess(this->Info, Type, Result,
8275 Adjustments[I].Ptr.RHS))
8276 return false;
8277 Type = Adjustments[I].Ptr.MPT->getPointeeType();
8278 break;
8279 }
8280 }
8281
8282 return true;
8283}
8284
8285bool
8286LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
8287 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
8288 "lvalue compound literal in c++?");
8289 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
8290 // only see this when folding in C, so there's no standard to follow here.
8291 return Success(E);
8292}
8293
8294bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
8295 TypeInfoLValue TypeInfo;
8296
8297 if (!E->isPotentiallyEvaluated()) {
8298 if (E->isTypeOperand())
8299 TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr());
8300 else
8301 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr());
8302 } else {
8303 if (!Info.Ctx.getLangOpts().CPlusPlus20) {
8304 Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic)
8305 << E->getExprOperand()->getType()
8306 << E->getExprOperand()->getSourceRange();
8307 }
8308
8309 if (!Visit(E->getExprOperand()))
8310 return false;
8311
8312 Optional<DynamicType> DynType =
8313 ComputeDynamicType(Info, E, Result, AK_TypeId);
8314 if (!DynType)
8315 return false;
8316
8317 TypeInfo =
8318 TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr());
8319 }
8320
8321 return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType()));
8322}
8323
8324bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
8325 return Success(E->getGuidDecl());
8326}
8327
8328bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
8329 // Handle static data members.
8330 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
8331 VisitIgnoredBaseExpression(E->getBase());
8332 return VisitVarDecl(E, VD);
8333 }
8334
8335 // Handle static member functions.
8336 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
8337 if (MD->isStatic()) {
8338 VisitIgnoredBaseExpression(E->getBase());
8339 return Success(MD);
8340 }
8341 }
8342
8343 // Handle non-static data members.
8344 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E);
8345}
8346
8347bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) {
8348 // FIXME: Deal with vectors as array subscript bases.
8349 if (E->getBase()->getType()->isVectorType())
8350 return Error(E);
8351
8352 APSInt Index;
8353 bool Success = true;
8354
8355 // C++17's rules require us to evaluate the LHS first, regardless of which
8356 // side is the base.
8357 for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) {
8358 if (SubExpr == E->getBase() ? !evaluatePointer(SubExpr, Result)
8359 : !EvaluateInteger(SubExpr, Index, Info)) {
8360 if (!Info.noteFailure())
8361 return false;
8362 Success = false;
8363 }
8364 }
8365
8366 return Success &&
8367 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index);
8368}
8369
8370bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
8371 return evaluatePointer(E->getSubExpr(), Result);
8372}
8373
8374bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
8375 if (!Visit(E->getSubExpr()))
8376 return false;
8377 // __real is a no-op on scalar lvalues.
8378 if (E->getSubExpr()->getType()->isAnyComplexType())
8379 HandleLValueComplexElement(Info, E, Result, E->getType(), false);
8380 return true;
8381}
8382
8383bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
8384 assert(E->getSubExpr()->getType()->isAnyComplexType() &&
8385 "lvalue __imag__ on scalar?");
8386 if (!Visit(E->getSubExpr()))
8387 return false;
8388 HandleLValueComplexElement(Info, E, Result, E->getType(), true);
8389 return true;
8390}
8391
8392bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) {
8393 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8394 return Error(UO);
8395
8396 if (!this->Visit(UO->getSubExpr()))
8397 return false;
8398
8399 return handleIncDec(
8400 this->Info, UO, Result, UO->getSubExpr()->getType(),
8401 UO->isIncrementOp(), nullptr);
8402}
8403
8404bool LValueExprEvaluator::VisitCompoundAssignOperator(
8405 const CompoundAssignOperator *CAO) {
8406 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8407 return Error(CAO);
8408
8409 bool Success = true;
8410
8411 // C++17 onwards require that we evaluate the RHS first.
8412 APValue RHS;
8413 if (!Evaluate(RHS, this->Info, CAO->getRHS())) {
8414 if (!Info.noteFailure())
8415 return false;
8416 Success = false;
8417 }
8418
8419 // The overall lvalue result is the result of evaluating the LHS.
8420 if (!this->Visit(CAO->getLHS()) || !Success)
8421 return false;
8422
8423 return handleCompoundAssignment(
8424 this->Info, CAO,
8425 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(),
8426 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS);
8427}
8428
8429bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) {
8430 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure())
8431 return Error(E);
8432
8433 bool Success = true;
8434
8435 // C++17 onwards require that we evaluate the RHS first.
8436 APValue NewVal;
8437 if (!Evaluate(NewVal, this->Info, E->getRHS())) {
8438 if (!Info.noteFailure())
8439 return false;
8440 Success = false;
8441 }
8442
8443 if (!this->Visit(E->getLHS()) || !Success)
8444 return false;
8445
8446 if (Info.getLangOpts().CPlusPlus20 &&
8447 !HandleUnionActiveMemberChange(Info, E->getLHS(), Result))
8448 return false;
8449
8450 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(),
8451 NewVal);
8452}
8453
8454//===----------------------------------------------------------------------===//
8455// Pointer Evaluation
8456//===----------------------------------------------------------------------===//
8457
8458/// Attempts to compute the number of bytes available at the pointer
8459/// returned by a function with the alloc_size attribute. Returns true if we
8460/// were successful. Places an unsigned number into `Result`.
8461///
8462/// This expects the given CallExpr to be a call to a function with an
8463/// alloc_size attribute.
8464static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8465 const CallExpr *Call,
8466 llvm::APInt &Result) {
8467 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call);
8468
8469 assert(AllocSize && AllocSize->getElemSizeParam().isValid());
8470 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex();
8471 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType());
8472 if (Call->getNumArgs() <= SizeArgNo)
8473 return false;
8474
8475 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) {
8476 Expr::EvalResult ExprResult;
8477 if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects))
8478 return false;
8479 Into = ExprResult.Val.getInt();
8480 if (Into.isNegative() || !Into.isIntN(BitsInSizeT))
8481 return false;
8482 Into = Into.zextOrSelf(BitsInSizeT);
8483 return true;
8484 };
8485
8486 APSInt SizeOfElem;
8487 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem))
8488 return false;
8489
8490 if (!AllocSize->getNumElemsParam().isValid()) {
8491 Result = std::move(SizeOfElem);
8492 return true;
8493 }
8494
8495 APSInt NumberOfElems;
8496 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex();
8497 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems))
8498 return false;
8499
8500 bool Overflow;
8501 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow);
8502 if (Overflow)
8503 return false;
8504
8505 Result = std::move(BytesAvailable);
8506 return true;
8507}
8508
8509/// Convenience function. LVal's base must be a call to an alloc_size
8510/// function.
8511static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx,
8512 const LValue &LVal,
8513 llvm::APInt &Result) {
8514 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
8515 "Can't get the size of a non alloc_size function");
8516 const auto *Base = LVal.getLValueBase().get<const Expr *>();
8517 const CallExpr *CE = tryUnwrapAllocSizeCall(Base);
8518 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result);
8519}
8520
8521/// Attempts to evaluate the given LValueBase as the result of a call to
8522/// a function with the alloc_size attribute. If it was possible to do so, this
8523/// function will return true, make Result's Base point to said function call,
8524/// and mark Result's Base as invalid.
8525static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
8526 LValue &Result) {
8527 if (Base.isNull())
8528 return false;
8529
8530 // Because we do no form of static analysis, we only support const variables.
8531 //
8532 // Additionally, we can't support parameters, nor can we support static
8533 // variables (in the latter case, use-before-assign isn't UB; in the former,
8534 // we have no clue what they'll be assigned to).
8535 const auto *VD =
8536 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>());
8537 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified())
8538 return false;
8539
8540 const Expr *Init = VD->getAnyInitializer();
8541 if (!Init)
8542 return false;
8543
8544 const Expr *E = Init->IgnoreParens();
8545 if (!tryUnwrapAllocSizeCall(E))
8546 return false;
8547
8548 // Store E instead of E unwrapped so that the type of the LValue's base is
8549 // what the user wanted.
8550 Result.setInvalid(E);
8551
8552 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType();
8553 Result.addUnsizedArray(Info, E, Pointee);
8554 return true;
8555}
8556
8557namespace {
8558class PointerExprEvaluator
8559 : public ExprEvaluatorBase<PointerExprEvaluator> {
8560 LValue &Result;
8561 bool InvalidBaseOK;
8562
8563 bool Success(const Expr *E) {
8564 Result.set(E);
8565 return true;
8566 }
8567
8568 bool evaluateLValue(const Expr *E, LValue &Result) {
8569 return EvaluateLValue(E, Result, Info, InvalidBaseOK);
8570 }
8571
8572 bool evaluatePointer(const Expr *E, LValue &Result) {
8573 return EvaluatePointer(E, Result, Info, InvalidBaseOK);
8574 }
8575
8576 bool visitNonBuiltinCallExpr(const CallExpr *E);
8577public:
8578
8579 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK)
8580 : ExprEvaluatorBaseTy(info), Result(Result),
8581 InvalidBaseOK(InvalidBaseOK) {}
8582
8583 bool Success(const APValue &V, const Expr *E) {
8584 Result.setFrom(Info.Ctx, V);
8585 return true;
8586 }
8587 bool ZeroInitialization(const Expr *E) {
8588 Result.setNull(Info.Ctx, E->getType());
8589 return true;
8590 }
8591
8592 bool VisitBinaryOperator(const BinaryOperator *E);
8593 bool VisitCastExpr(const CastExpr* E);
8594 bool VisitUnaryAddrOf(const UnaryOperator *E);
8595 bool VisitObjCStringLiteral(const ObjCStringLiteral *E)
8596 { return Success(E); }
8597 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
8598 if (E->isExpressibleAsConstantInitializer())
8599 return Success(E);
8600 if (Info.noteFailure())
8601 EvaluateIgnoredValue(Info, E->getSubExpr());
8602 return Error(E);
8603 }
8604 bool VisitAddrLabelExpr(const AddrLabelExpr *E)
8605 { return Success(E); }
8606 bool VisitCallExpr(const CallExpr *E);
8607 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
8608 bool VisitBlockExpr(const BlockExpr *E) {
8609 if (!E->getBlockDecl()->hasCaptures())
8610 return Success(E);
8611 return Error(E);
8612 }
8613 bool VisitCXXThisExpr(const CXXThisExpr *E) {
8614 // Can't look at 'this' when checking a potential constant expression.
8615 if (Info.checkingPotentialConstantExpression())
8616 return false;
8617 if (!Info.CurrentCall->This) {
8618 if (Info.getLangOpts().CPlusPlus11)
8619 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit();
8620 else
8621 Info.FFDiag(E);
8622 return false;
8623 }
8624 Result = *Info.CurrentCall->This;
8625 // If we are inside a lambda's call operator, the 'this' expression refers
8626 // to the enclosing '*this' object (either by value or reference) which is
8627 // either copied into the closure object's field that represents the '*this'
8628 // or refers to '*this'.
8629 if (isLambdaCallOperator(Info.CurrentCall->Callee)) {
8630 // Ensure we actually have captured 'this'. (an error will have
8631 // been previously reported if not).
8632 if (!Info.CurrentCall->LambdaThisCaptureField)
8633 return false;
8634
8635 // Update 'Result' to refer to the data member/field of the closure object
8636 // that represents the '*this' capture.
8637 if (!HandleLValueMember(Info, E, Result,
8638 Info.CurrentCall->LambdaThisCaptureField))
8639 return false;
8640 // If we captured '*this' by reference, replace the field with its referent.
8641 if (Info.CurrentCall->LambdaThisCaptureField->getType()
8642 ->isPointerType()) {
8643 APValue RVal;
8644 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result,
8645 RVal))
8646 return false;
8647
8648 Result.setFrom(Info.Ctx, RVal);
8649 }
8650 }
8651 return true;
8652 }
8653
8654 bool VisitCXXNewExpr(const CXXNewExpr *E);
8655
8656 bool VisitSourceLocExpr(const SourceLocExpr *E) {
8657 assert(E->isStringType() && "SourceLocExpr isn't a pointer type?");
8658 APValue LValResult = E->EvaluateInContext(
8659 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
8660 Result.setFrom(Info.Ctx, LValResult);
8661 return true;
8662 }
8663
8664 // FIXME: Missing: @protocol, @selector
8665};
8666} // end anonymous namespace
8667
8668static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info,
8669 bool InvalidBaseOK) {
8670 assert(!E->isValueDependent());
8671 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
8672 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E);
8673}
8674
8675bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
8676 if (E->getOpcode() != BO_Add &&
8677 E->getOpcode() != BO_Sub)
8678 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
8679
8680 const Expr *PExp = E->getLHS();
8681 const Expr *IExp = E->getRHS();
8682 if (IExp->getType()->isPointerType())
8683 std::swap(PExp, IExp);
8684
8685 bool EvalPtrOK = evaluatePointer(PExp, Result);
8686 if (!EvalPtrOK && !Info.noteFailure())
8687 return false;
8688
8689 llvm::APSInt Offset;
8690 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
8691 return false;
8692
8693 if (E->getOpcode() == BO_Sub)
8694 negateAsSigned(Offset);
8695
8696 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType();
8697 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset);
8698}
8699
8700bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
8701 return evaluateLValue(E->getSubExpr(), Result);
8702}
8703
8704bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
8705 const Expr *SubExpr = E->getSubExpr();
8706
8707 switch (E->getCastKind()) {
8708 default:
8709 break;
8710 case CK_BitCast:
8711 case CK_CPointerToObjCPointerCast:
8712 case CK_BlockPointerToObjCPointerCast:
8713 case CK_AnyPointerToBlockPointerCast:
8714 case CK_AddressSpaceConversion:
8715 if (!Visit(SubExpr))
8716 return false;
8717 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are
8718 // permitted in constant expressions in C++11. Bitcasts from cv void* are
8719 // also static_casts, but we disallow them as a resolution to DR1312.
8720 if (!E->getType()->isVoidPointerType()) {
8721 if (!Result.InvalidBase && !Result.Designator.Invalid &&
8722 !Result.IsNullPtr &&
8723 Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx),
8724 E->getType()->getPointeeType()) &&
8725 Info.getStdAllocatorCaller("allocate")) {
8726 // Inside a call to std::allocator::allocate and friends, we permit
8727 // casting from void* back to cv1 T* for a pointer that points to a
8728 // cv2 T.
8729 } else {
8730 Result.Designator.setInvalid();
8731 if (SubExpr->getType()->isVoidPointerType())
8732 CCEDiag(E, diag::note_constexpr_invalid_cast)
8733 << 3 << SubExpr->getType();
8734 else
8735 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8736 }
8737 }
8738 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr)
8739 ZeroInitialization(E);
8740 return true;
8741
8742 case CK_DerivedToBase:
8743 case CK_UncheckedDerivedToBase:
8744 if (!evaluatePointer(E->getSubExpr(), Result))
8745 return false;
8746 if (!Result.Base && Result.Offset.isZero())
8747 return true;
8748
8749 // Now figure out the necessary offset to add to the base LV to get from
8750 // the derived class to the base class.
8751 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()->
8752 castAs<PointerType>()->getPointeeType(),
8753 Result);
8754
8755 case CK_BaseToDerived:
8756 if (!Visit(E->getSubExpr()))
8757 return false;
8758 if (!Result.Base && Result.Offset.isZero())
8759 return true;
8760 return HandleBaseToDerivedCast(Info, E, Result);
8761
8762 case CK_Dynamic:
8763 if (!Visit(E->getSubExpr()))
8764 return false;
8765 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result);
8766
8767 case CK_NullToPointer:
8768 VisitIgnoredValue(E->getSubExpr());
8769 return ZeroInitialization(E);
8770
8771 case CK_IntegralToPointer: {
8772 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
8773
8774 APValue Value;
8775 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info))
8776 break;
8777
8778 if (Value.isInt()) {
8779 unsigned Size = Info.Ctx.getTypeSize(E->getType());
8780 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue();
8781 Result.Base = (Expr*)nullptr;
8782 Result.InvalidBase = false;
8783 Result.Offset = CharUnits::fromQuantity(N);
8784 Result.Designator.setInvalid();
8785 Result.IsNullPtr = false;
8786 return true;
8787 } else {
8788 // Cast is of an lvalue, no need to change value.
8789 Result.setFrom(Info.Ctx, Value);
8790 return true;
8791 }
8792 }
8793
8794 case CK_ArrayToPointerDecay: {
8795 if (SubExpr->isGLValue()) {
8796 if (!evaluateLValue(SubExpr, Result))
8797 return false;
8798 } else {
8799 APValue &Value = Info.CurrentCall->createTemporary(
8800 SubExpr, SubExpr->getType(), ScopeKind::FullExpression, Result);
8801 if (!EvaluateInPlace(Value, Info, Result, SubExpr))
8802 return false;
8803 }
8804 // The result is a pointer to the first element of the array.
8805 auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType());
8806 if (auto *CAT = dyn_cast<ConstantArrayType>(AT))
8807 Result.addArray(Info, E, CAT);
8808 else
8809 Result.addUnsizedArray(Info, E, AT->getElementType());
8810 return true;
8811 }
8812
8813 case CK_FunctionToPointerDecay:
8814 return evaluateLValue(SubExpr, Result);
8815
8816 case CK_LValueToRValue: {
8817 LValue LVal;
8818 if (!evaluateLValue(E->getSubExpr(), LVal))
8819 return false;
8820
8821 APValue RVal;
8822 // Note, we use the subexpression's type in order to retain cv-qualifiers.
8823 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(),
8824 LVal, RVal))
8825 return InvalidBaseOK &&
8826 evaluateLValueAsAllocSize(Info, LVal.Base, Result);
8827 return Success(RVal, E);
8828 }
8829 }
8830
8831 return ExprEvaluatorBaseTy::VisitCastExpr(E);
8832}
8833
8834static CharUnits GetAlignOfType(EvalInfo &Info, QualType T,
8835 UnaryExprOrTypeTrait ExprKind) {
8836 // C++ [expr.alignof]p3:
8837 // When alignof is applied to a reference type, the result is the
8838 // alignment of the referenced type.
8839 if (const ReferenceType *Ref = T->getAs<ReferenceType>())
8840 T = Ref->getPointeeType();
8841
8842 if (T.getQualifiers().hasUnaligned())
8843 return CharUnits::One();
8844
8845 const bool AlignOfReturnsPreferred =
8846 Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7;
8847
8848 // __alignof is defined to return the preferred alignment.
8849 // Before 8, clang returned the preferred alignment for alignof and _Alignof
8850 // as well.
8851 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred)
8852 return Info.Ctx.toCharUnitsFromBits(
8853 Info.Ctx.getPreferredTypeAlign(T.getTypePtr()));
8854 // alignof and _Alignof are defined to return the ABI alignment.
8855 else if (ExprKind == UETT_AlignOf)
8856 return Info.Ctx.getTypeAlignInChars(T.getTypePtr());
8857 else
8858 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind");
8859}
8860
8861static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E,
8862 UnaryExprOrTypeTrait ExprKind) {
8863 E = E->IgnoreParens();
8864
8865 // The kinds of expressions that we have special-case logic here for
8866 // should be kept up to date with the special checks for those
8867 // expressions in Sema.
8868
8869 // alignof decl is always accepted, even if it doesn't make sense: we default
8870 // to 1 in those cases.
8871 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
8872 return Info.Ctx.getDeclAlign(DRE->getDecl(),
8873 /*RefAsPointee*/true);
8874
8875 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
8876 return Info.Ctx.getDeclAlign(ME->getMemberDecl(),
8877 /*RefAsPointee*/true);
8878
8879 return GetAlignOfType(Info, E->getType(), ExprKind);
8880}
8881
8882static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) {
8883 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>())
8884 return Info.Ctx.getDeclAlign(VD);
8885 if (const auto *E = Value.Base.dyn_cast<const Expr *>())
8886 return GetAlignOfExpr(Info, E, UETT_AlignOf);
8887 return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf);
8888}
8889
8890/// Evaluate the value of the alignment argument to __builtin_align_{up,down},
8891/// __builtin_is_aligned and __builtin_assume_aligned.
8892static bool getAlignmentArgument(const Expr *E, QualType ForType,
8893 EvalInfo &Info, APSInt &Alignment) {
8894 if (!EvaluateInteger(E, Alignment, Info))
8895 return false;
8896 if (Alignment < 0 || !Alignment.isPowerOf2()) {
8897 Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment;
8898 return false;
8899 }
8900 unsigned SrcWidth = Info.Ctx.getIntWidth(ForType);
8901 APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1));
8902 if (APSInt::compareValues(Alignment, MaxValue) > 0) {
8903 Info.FFDiag(E, diag::note_constexpr_alignment_too_big)
8904 << MaxValue << ForType << Alignment;
8905 return false;
8906 }
8907 // Ensure both alignment and source value have the same bit width so that we
8908 // don't assert when computing the resulting value.
8909 APSInt ExtAlignment =
8910 APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true);
8911 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 &&
8912 "Alignment should not be changed by ext/trunc");
8913 Alignment = ExtAlignment;
8914 assert(Alignment.getBitWidth() == SrcWidth);
8915 return true;
8916}
8917
8918// To be clear: this happily visits unsupported builtins. Better name welcomed.
8919bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) {
8920 if (ExprEvaluatorBaseTy::VisitCallExpr(E))
8921 return true;
8922
8923 if (!(InvalidBaseOK && getAllocSizeAttr(E)))
8924 return false;
8925
8926 Result.setInvalid(E);
8927 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType();
8928 Result.addUnsizedArray(Info, E, PointeeTy);
8929 return true;
8930}
8931
8932bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) {
8933 if (IsStringLiteralCall(E))
8934 return Success(E);
8935
8936 if (unsigned BuiltinOp = E->getBuiltinCallee())
8937 return VisitBuiltinCallExpr(E, BuiltinOp);
8938
8939 return visitNonBuiltinCallExpr(E);
8940}
8941
8942// Determine if T is a character type for which we guarantee that
8943// sizeof(T) == 1.
8944static bool isOneByteCharacterType(QualType T) {
8945 return T->isCharType() || T->isChar8Type();
8946}
8947
8948bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
8949 unsigned BuiltinOp) {
8950 switch (BuiltinOp) {
8951 case Builtin::BI__builtin_addressof:
8952 return evaluateLValue(E->getArg(0), Result);
8953 case Builtin::BI__builtin_assume_aligned: {
8954 // We need to be very careful here because: if the pointer does not have the
8955 // asserted alignment, then the behavior is undefined, and undefined
8956 // behavior is non-constant.
8957 if (!evaluatePointer(E->getArg(0), Result))
8958 return false;
8959
8960 LValue OffsetResult(Result);
8961 APSInt Alignment;
8962 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
8963 Alignment))
8964 return false;
8965 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
8966
8967 if (E->getNumArgs() > 2) {
8968 APSInt Offset;
8969 if (!EvaluateInteger(E->getArg(2), Offset, Info))
8970 return false;
8971
8972 int64_t AdditionalOffset = -Offset.getZExtValue();
8973 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
8974 }
8975
8976 // If there is a base object, then it must have the correct alignment.
8977 if (OffsetResult.Base) {
8978 CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult);
8979
8980 if (BaseAlignment < Align) {
8981 Result.Designator.setInvalid();
8982 // FIXME: Add support to Diagnostic for long / long long.
8983 CCEDiag(E->getArg(0),
8984 diag::note_constexpr_baa_insufficient_alignment) << 0
8985 << (unsigned)BaseAlignment.getQuantity()
8986 << (unsigned)Align.getQuantity();
8987 return false;
8988 }
8989 }
8990
8991 // The offset must also have the correct alignment.
8992 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
8993 Result.Designator.setInvalid();
8994
8995 (OffsetResult.Base
8996 ? CCEDiag(E->getArg(0),
8997 diag::note_constexpr_baa_insufficient_alignment) << 1
8998 : CCEDiag(E->getArg(0),
8999 diag::note_constexpr_baa_value_insufficient_alignment))
9000 << (int)OffsetResult.Offset.getQuantity()
9001 << (unsigned)Align.getQuantity();
9002 return false;
9003 }
9004
9005 return true;
9006 }
9007 case Builtin::BI__builtin_align_up:
9008 case Builtin::BI__builtin_align_down: {
9009 if (!evaluatePointer(E->getArg(0), Result))
9010 return false;
9011 APSInt Alignment;
9012 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info,
9013 Alignment))
9014 return false;
9015 CharUnits BaseAlignment = getBaseAlignment(Info, Result);
9016 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset);
9017 // For align_up/align_down, we can return the same value if the alignment
9018 // is known to be greater or equal to the requested value.
9019 if (PtrAlign.getQuantity() >= Alignment)
9020 return true;
9021
9022 // The alignment could be greater than the minimum at run-time, so we cannot
9023 // infer much about the resulting pointer value. One case is possible:
9024 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we
9025 // can infer the correct index if the requested alignment is smaller than
9026 // the base alignment so we can perform the computation on the offset.
9027 if (BaseAlignment.getQuantity() >= Alignment) {
9028 assert(Alignment.getBitWidth() <= 64 &&
9029 "Cannot handle > 64-bit address-space");
9030 uint64_t Alignment64 = Alignment.getZExtValue();
9031 CharUnits NewOffset = CharUnits::fromQuantity(
9032 BuiltinOp == Builtin::BI__builtin_align_down
9033 ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64)
9034 : llvm::alignTo(Result.Offset.getQuantity(), Alignment64));
9035 Result.adjustOffset(NewOffset - Result.Offset);
9036 // TODO: diagnose out-of-bounds values/only allow for arrays?
9037 return true;
9038 }
9039 // Otherwise, we cannot constant-evaluate the result.
9040 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust)
9041 << Alignment;
9042 return false;
9043 }
9044 case Builtin::BI__builtin_operator_new:
9045 return HandleOperatorNewCall(Info, E, Result);
9046 case Builtin::BI__builtin_launder:
9047 return evaluatePointer(E->getArg(0), Result);
9048 case Builtin::BIstrchr:
9049 case Builtin::BIwcschr:
9050 case Builtin::BImemchr:
9051 case Builtin::BIwmemchr:
9052 if (Info.getLangOpts().CPlusPlus11)
9053 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9054 << /*isConstexpr*/0 << /*isConstructor*/0
9055 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
9056 else
9057 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9058 LLVM_FALLTHROUGH;
9059 case Builtin::BI__builtin_strchr:
9060 case Builtin::BI__builtin_wcschr:
9061 case Builtin::BI__builtin_memchr:
9062 case Builtin::BI__builtin_char_memchr:
9063 case Builtin::BI__builtin_wmemchr: {
9064 if (!Visit(E->getArg(0)))
9065 return false;
9066 APSInt Desired;
9067 if (!EvaluateInteger(E->getArg(1), Desired, Info))
9068 return false;
9069 uint64_t MaxLength = uint64_t(-1);
9070 if (BuiltinOp != Builtin::BIstrchr &&
9071 BuiltinOp != Builtin::BIwcschr &&
9072 BuiltinOp != Builtin::BI__builtin_strchr &&
9073 BuiltinOp != Builtin::BI__builtin_wcschr) {
9074 APSInt N;
9075 if (!EvaluateInteger(E->getArg(2), N, Info))
9076 return false;
9077 MaxLength = N.getExtValue();
9078 }
9079 // We cannot find the value if there are no candidates to match against.
9080 if (MaxLength == 0u)
9081 return ZeroInitialization(E);
9082 if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
9083 Result.Designator.Invalid)
9084 return false;
9085 QualType CharTy = Result.Designator.getType(Info.Ctx);
9086 bool IsRawByte = BuiltinOp == Builtin::BImemchr ||
9087 BuiltinOp == Builtin::BI__builtin_memchr;
9088 assert(IsRawByte ||
9089 Info.Ctx.hasSameUnqualifiedType(
9090 CharTy, E->getArg(0)->getType()->getPointeeType()));
9091 // Pointers to const void may point to objects of incomplete type.
9092 if (IsRawByte && CharTy->isIncompleteType()) {
9093 Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy;
9094 return false;
9095 }
9096 // Give up on byte-oriented matching against multibyte elements.
9097 // FIXME: We can compare the bytes in the correct order.
9098 if (IsRawByte && !isOneByteCharacterType(CharTy)) {
9099 Info.FFDiag(E, diag::note_constexpr_memchr_unsupported)
9100 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
9101 << CharTy;
9102 return false;
9103 }
9104 // Figure out what value we're actually looking for (after converting to
9105 // the corresponding unsigned type if necessary).
9106 uint64_t DesiredVal;
9107 bool StopAtNull = false;
9108 switch (BuiltinOp) {
9109 case Builtin::BIstrchr:
9110 case Builtin::BI__builtin_strchr:
9111 // strchr compares directly to the passed integer, and therefore
9112 // always fails if given an int that is not a char.
9113 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy,
9114 E->getArg(1)->getType(),
9115 Desired),
9116 Desired))
9117 return ZeroInitialization(E);
9118 StopAtNull = true;
9119 LLVM_FALLTHROUGH;
9120 case Builtin::BImemchr:
9121 case Builtin::BI__builtin_memchr:
9122 case Builtin::BI__builtin_char_memchr:
9123 // memchr compares by converting both sides to unsigned char. That's also
9124 // correct for strchr if we get this far (to cope with plain char being
9125 // unsigned in the strchr case).
9126 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue();
9127 break;
9128
9129 case Builtin::BIwcschr:
9130 case Builtin::BI__builtin_wcschr:
9131 StopAtNull = true;
9132 LLVM_FALLTHROUGH;
9133 case Builtin::BIwmemchr:
9134 case Builtin::BI__builtin_wmemchr:
9135 // wcschr and wmemchr are given a wchar_t to look for. Just use it.
9136 DesiredVal = Desired.getZExtValue();
9137 break;
9138 }
9139
9140 for (; MaxLength; --MaxLength) {
9141 APValue Char;
9142 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) ||
9143 !Char.isInt())
9144 return false;
9145 if (Char.getInt().getZExtValue() == DesiredVal)
9146 return true;
9147 if (StopAtNull && !Char.getInt())
9148 break;
9149 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1))
9150 return false;
9151 }
9152 // Not found: return nullptr.
9153 return ZeroInitialization(E);
9154 }
9155
9156 case Builtin::BImemcpy:
9157 case Builtin::BImemmove:
9158 case Builtin::BIwmemcpy:
9159 case Builtin::BIwmemmove:
9160 if (Info.getLangOpts().CPlusPlus11)
9161 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
9162 << /*isConstexpr*/0 << /*isConstructor*/0
9163 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
9164 else
9165 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
9166 LLVM_FALLTHROUGH;
9167 case Builtin::BI__builtin_memcpy:
9168 case Builtin::BI__builtin_memmove:
9169 case Builtin::BI__builtin_wmemcpy:
9170 case Builtin::BI__builtin_wmemmove: {
9171 bool WChar = BuiltinOp == Builtin::BIwmemcpy ||
9172 BuiltinOp == Builtin::BIwmemmove ||
9173 BuiltinOp == Builtin::BI__builtin_wmemcpy ||
9174 BuiltinOp == Builtin::BI__builtin_wmemmove;
9175 bool Move = BuiltinOp == Builtin::BImemmove ||
9176 BuiltinOp == Builtin::BIwmemmove ||
9177 BuiltinOp == Builtin::BI__builtin_memmove ||
9178 BuiltinOp == Builtin::BI__builtin_wmemmove;
9179
9180 // The result of mem* is the first argument.
9181 if (!Visit(E->getArg(0)))
9182 return false;
9183 LValue Dest = Result;
9184
9185 LValue Src;
9186 if (!EvaluatePointer(E->getArg(1), Src, Info))
9187 return false;
9188
9189 APSInt N;
9190 if (!EvaluateInteger(E->getArg(2), N, Info))
9191 return false;
9192 assert(!N.isSigned() && "memcpy and friends take an unsigned size");
9193
9194 // If the size is zero, we treat this as always being a valid no-op.
9195 // (Even if one of the src and dest pointers is null.)
9196 if (!N)
9197 return true;
9198
9199 // Otherwise, if either of the operands is null, we can't proceed. Don't
9200 // try to determine the type of the copied objects, because there aren't
9201 // any.
9202 if (!Src.Base || !Dest.Base) {
9203 APValue Val;
9204 (!Src.Base ? Src : Dest).moveInto(Val);
9205 Info.FFDiag(E, diag::note_constexpr_memcpy_null)
9206 << Move << WChar << !!Src.Base
9207 << Val.getAsString(Info.Ctx, E->getArg(0)->getType());
9208 return false;
9209 }
9210 if (Src.Designator.Invalid || Dest.Designator.Invalid)
9211 return false;
9212
9213 // We require that Src and Dest are both pointers to arrays of
9214 // trivially-copyable type. (For the wide version, the designator will be
9215 // invalid if the designated object is not a wchar_t.)
9216 QualType T = Dest.Designator.getType(Info.Ctx);
9217 QualType SrcT = Src.Designator.getType(Info.Ctx);
9218 if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) {
9219 // FIXME: Consider using our bit_cast implementation to support this.
9220 Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T;
9221 return false;
9222 }
9223 if (T->isIncompleteType()) {
9224 Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T;
9225 return false;
9226 }
9227 if (!T.isTriviallyCopyableType(Info.Ctx)) {
9228 Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T;
9229 return false;
9230 }
9231
9232 // Figure out how many T's we're copying.
9233 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity();
9234 if (!WChar) {
9235 uint64_t Remainder;
9236 llvm::APInt OrigN = N;
9237 llvm::APInt::udivrem(OrigN, TSize, N, Remainder);
9238 if (Remainder) {
9239 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9240 << Move << WChar << 0 << T << OrigN.toString(10, /*Signed*/false)
9241 << (unsigned)TSize;
9242 return false;
9243 }
9244 }
9245
9246 // Check that the copying will remain within the arrays, just so that we
9247 // can give a more meaningful diagnostic. This implicitly also checks that
9248 // N fits into 64 bits.
9249 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second;
9250 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second;
9251 if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) {
9252 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported)
9253 << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T
9254 << N.toString(10, /*Signed*/false);
9255 return false;
9256 }
9257 uint64_t NElems = N.getZExtValue();
9258 uint64_t NBytes = NElems * TSize;
9259
9260 // Check for overlap.
9261 int Direction = 1;
9262 if (HasSameBase(Src, Dest)) {
9263 uint64_t SrcOffset = Src.getLValueOffset().getQuantity();
9264 uint64_t DestOffset = Dest.getLValueOffset().getQuantity();
9265 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) {
9266 // Dest is inside the source region.
9267 if (!Move) {
9268 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9269 return false;
9270 }
9271 // For memmove and friends, copy backwards.
9272 if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) ||
9273 !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1))
9274 return false;
9275 Direction = -1;
9276 } else if (!Move && SrcOffset >= DestOffset &&
9277 SrcOffset - DestOffset < NBytes) {
9278 // Src is inside the destination region for memcpy: invalid.
9279 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar;
9280 return false;
9281 }
9282 }
9283
9284 while (true) {
9285 APValue Val;
9286 // FIXME: Set WantObjectRepresentation to true if we're copying a
9287 // char-like type?
9288 if (!handleLValueToRValueConversion(Info, E, T, Src, Val) ||
9289 !handleAssignment(Info, E, Dest, T, Val))
9290 return false;
9291 // Do not iterate past the last element; if we're copying backwards, that
9292 // might take us off the start of the array.
9293 if (--NElems == 0)
9294 return true;
9295 if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) ||
9296 !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction))
9297 return false;
9298 }
9299 }
9300
9301 default:
9302 break;
9303 }
9304
9305 return visitNonBuiltinCallExpr(E);
9306}
9307
9308static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
9309 APValue &Result, const InitListExpr *ILE,
9310 QualType AllocType);
9311static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
9312 APValue &Result,
9313 const CXXConstructExpr *CCE,
9314 QualType AllocType);
9315
9316bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) {
9317 if (!Info.getLangOpts().CPlusPlus20)
9318 Info.CCEDiag(E, diag::note_constexpr_new);
9319
9320 // We cannot speculatively evaluate a delete expression.
9321 if (Info.SpeculativeEvaluationDepth)
9322 return false;
9323
9324 FunctionDecl *OperatorNew = E->getOperatorNew();
9325
9326 bool IsNothrow = false;
9327 bool IsPlacement = false;
9328 if (OperatorNew->isReservedGlobalPlacementOperator() &&
9329 Info.CurrentCall->isStdFunction() && !E->isArray()) {
9330 // FIXME Support array placement new.
9331 assert(E->getNumPlacementArgs() == 1);
9332 if (!EvaluatePointer(E->getPlacementArg(0), Result, Info))
9333 return false;
9334 if (Result.Designator.Invalid)
9335 return false;
9336 IsPlacement = true;
9337 } else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) {
9338 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
9339 << isa<CXXMethodDecl>(OperatorNew) << OperatorNew;
9340 return false;
9341 } else if (E->getNumPlacementArgs()) {
9342 // The only new-placement list we support is of the form (std::nothrow).
9343 //
9344 // FIXME: There is no restriction on this, but it's not clear that any
9345 // other form makes any sense. We get here for cases such as:
9346 //
9347 // new (std::align_val_t{N}) X(int)
9348 //
9349 // (which should presumably be valid only if N is a multiple of
9350 // alignof(int), and in any case can't be deallocated unless N is
9351 // alignof(X) and X has new-extended alignment).
9352 if (E->getNumPlacementArgs() != 1 ||
9353 !E->getPlacementArg(0)->getType()->isNothrowT())
9354 return Error(E, diag::note_constexpr_new_placement);
9355
9356 LValue Nothrow;
9357 if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info))
9358 return false;
9359 IsNothrow = true;
9360 }
9361
9362 const Expr *Init = E->getInitializer();
9363 const InitListExpr *ResizedArrayILE = nullptr;
9364 const CXXConstructExpr *ResizedArrayCCE = nullptr;
9365 bool ValueInit = false;
9366
9367 QualType AllocType = E->getAllocatedType();
9368 if (Optional<const Expr*> ArraySize = E->getArraySize()) {
9369 const Expr *Stripped = *ArraySize;
9370 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped);
9371 Stripped = ICE->getSubExpr())
9372 if (ICE->getCastKind() != CK_NoOp &&
9373 ICE->getCastKind() != CK_IntegralCast)
9374 break;
9375
9376 llvm::APSInt ArrayBound;
9377 if (!EvaluateInteger(Stripped, ArrayBound, Info))
9378 return false;
9379
9380 // C++ [expr.new]p9:
9381 // The expression is erroneous if:
9382 // -- [...] its value before converting to size_t [or] applying the
9383 // second standard conversion sequence is less than zero
9384 if (ArrayBound.isSigned() && ArrayBound.isNegative()) {
9385 if (IsNothrow)
9386 return ZeroInitialization(E);
9387
9388 Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative)
9389 << ArrayBound << (*ArraySize)->getSourceRange();
9390 return false;
9391 }
9392
9393 // -- its value is such that the size of the allocated object would
9394 // exceed the implementation-defined limit
9395 if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType,
9396 ArrayBound) >
9397 ConstantArrayType::getMaxSizeBits(Info.Ctx)) {
9398 if (IsNothrow)
9399 return ZeroInitialization(E);
9400
9401 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large)
9402 << ArrayBound << (*ArraySize)->getSourceRange();
9403 return false;
9404 }
9405
9406 // -- the new-initializer is a braced-init-list and the number of
9407 // array elements for which initializers are provided [...]
9408 // exceeds the number of elements to initialize
9409 if (!Init) {
9410 // No initialization is performed.
9411 } else if (isa<CXXScalarValueInitExpr>(Init) ||
9412 isa<ImplicitValueInitExpr>(Init)) {
9413 ValueInit = true;
9414 } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) {
9415 ResizedArrayCCE = CCE;
9416 } else {
9417 auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType());
9418 assert(CAT && "unexpected type for array initializer");
9419
9420 unsigned Bits =
9421 std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth());
9422 llvm::APInt InitBound = CAT->getSize().zextOrSelf(Bits);
9423 llvm::APInt AllocBound = ArrayBound.zextOrSelf(Bits);
9424 if (InitBound.ugt(AllocBound)) {
9425 if (IsNothrow)
9426 return ZeroInitialization(E);
9427
9428 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small)
9429 << AllocBound.toString(10, /*Signed=*/false)
9430 << InitBound.toString(10, /*Signed=*/false)
9431 << (*ArraySize)->getSourceRange();
9432 return false;
9433 }
9434
9435 // If the sizes differ, we must have an initializer list, and we need
9436 // special handling for this case when we initialize.
9437 if (InitBound != AllocBound)
9438 ResizedArrayILE = cast<InitListExpr>(Init);
9439 }
9440
9441 AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr,
9442 ArrayType::Normal, 0);
9443 } else {
9444 assert(!AllocType->isArrayType() &&
9445 "array allocation with non-array new");
9446 }
9447
9448 APValue *Val;
9449 if (IsPlacement) {
9450 AccessKinds AK = AK_Construct;
9451 struct FindObjectHandler {
9452 EvalInfo &Info;
9453 const Expr *E;
9454 QualType AllocType;
9455 const AccessKinds AccessKind;
9456 APValue *Value;
9457
9458 typedef bool result_type;
9459 bool failed() { return false; }
9460 bool found(APValue &Subobj, QualType SubobjType) {
9461 // FIXME: Reject the cases where [basic.life]p8 would not permit the
9462 // old name of the object to be used to name the new object.
9463 if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) {
9464 Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) <<
9465 SubobjType << AllocType;
9466 return false;
9467 }
9468 Value = &Subobj;
9469 return true;
9470 }
9471 bool found(APSInt &Value, QualType SubobjType) {
9472 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9473 return false;
9474 }
9475 bool found(APFloat &Value, QualType SubobjType) {
9476 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem);
9477 return false;
9478 }
9479 } Handler = {Info, E, AllocType, AK, nullptr};
9480
9481 CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType);
9482 if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler))
9483 return false;
9484
9485 Val = Handler.Value;
9486
9487 // [basic.life]p1:
9488 // The lifetime of an object o of type T ends when [...] the storage
9489 // which the object occupies is [...] reused by an object that is not
9490 // nested within o (6.6.2).
9491 *Val = APValue();
9492 } else {
9493 // Perform the allocation and obtain a pointer to the resulting object.
9494 Val = Info.createHeapAlloc(E, AllocType, Result);
9495 if (!Val)
9496 return false;
9497 }
9498
9499 if (ValueInit) {
9500 ImplicitValueInitExpr VIE(AllocType);
9501 if (!EvaluateInPlace(*Val, Info, Result, &VIE))
9502 return false;
9503 } else if (ResizedArrayILE) {
9504 if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE,
9505 AllocType))
9506 return false;
9507 } else if (ResizedArrayCCE) {
9508 if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE,
9509 AllocType))
9510 return false;
9511 } else if (Init) {
9512 if (!EvaluateInPlace(*Val, Info, Result, Init))
9513 return false;
9514 } else if (!getDefaultInitValue(AllocType, *Val)) {
9515 return false;
9516 }
9517
9518 // Array new returns a pointer to the first element, not a pointer to the
9519 // array.
9520 if (auto *AT = AllocType->getAsArrayTypeUnsafe())
9521 Result.addArray(Info, E, cast<ConstantArrayType>(AT));
9522
9523 return true;
9524}
9525//===----------------------------------------------------------------------===//
9526// Member Pointer Evaluation
9527//===----------------------------------------------------------------------===//
9528
9529namespace {
9530class MemberPointerExprEvaluator
9531 : public ExprEvaluatorBase<MemberPointerExprEvaluator> {
9532 MemberPtr &Result;
9533
9534 bool Success(const ValueDecl *D) {
9535 Result = MemberPtr(D);
9536 return true;
9537 }
9538public:
9539
9540 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result)
9541 : ExprEvaluatorBaseTy(Info), Result(Result) {}
9542
9543 bool Success(const APValue &V, const Expr *E) {
9544 Result.setFrom(V);
9545 return true;
9546 }
9547 bool ZeroInitialization(const Expr *E) {
9548 return Success((const ValueDecl*)nullptr);
9549 }
9550
9551 bool VisitCastExpr(const CastExpr *E);
9552 bool VisitUnaryAddrOf(const UnaryOperator *E);
9553};
9554} // end anonymous namespace
9555
9556static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result,
9557 EvalInfo &Info) {
9558 assert(!E->isValueDependent());
9559 assert(E->isRValue() && E->getType()->isMemberPointerType());
9560 return MemberPointerExprEvaluator(Info, Result).Visit(E);
9561}
9562
9563bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) {
9564 switch (E->getCastKind()) {
9565 default:
9566 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9567
9568 case CK_NullToMemberPointer:
9569 VisitIgnoredValue(E->getSubExpr());
9570 return ZeroInitialization(E);
9571
9572 case CK_BaseToDerivedMemberPointer: {
9573 if (!Visit(E->getSubExpr()))
9574 return false;
9575 if (E->path_empty())
9576 return true;
9577 // Base-to-derived member pointer casts store the path in derived-to-base
9578 // order, so iterate backwards. The CXXBaseSpecifier also provides us with
9579 // the wrong end of the derived->base arc, so stagger the path by one class.
9580 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter;
9581 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin());
9582 PathI != PathE; ++PathI) {
9583 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
9584 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl();
9585 if (!Result.castToDerived(Derived))
9586 return Error(E);
9587 }
9588 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass();
9589 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl()))
9590 return Error(E);
9591 return true;
9592 }
9593
9594 case CK_DerivedToBaseMemberPointer:
9595 if (!Visit(E->getSubExpr()))
9596 return false;
9597 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9598 PathE = E->path_end(); PathI != PathE; ++PathI) {
9599 assert(!(*PathI)->isVirtual() && "memptr cast through vbase");
9600 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9601 if (!Result.castToBase(Base))
9602 return Error(E);
9603 }
9604 return true;
9605 }
9606}
9607
9608bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) {
9609 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a
9610 // member can be formed.
9611 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl());
9612}
9613
9614//===----------------------------------------------------------------------===//
9615// Record Evaluation
9616//===----------------------------------------------------------------------===//
9617
9618namespace {
9619 class RecordExprEvaluator
9620 : public ExprEvaluatorBase<RecordExprEvaluator> {
9621 const LValue &This;
9622 APValue &Result;
9623 public:
9624
9625 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result)
9626 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {}
9627
9628 bool Success(const APValue &V, const Expr *E) {
9629 Result = V;
9630 return true;
9631 }
9632 bool ZeroInitialization(const Expr *E) {
9633 return ZeroInitialization(E, E->getType());
9634 }
9635 bool ZeroInitialization(const Expr *E, QualType T);
9636
9637 bool VisitCallExpr(const CallExpr *E) {
9638 return handleCallExpr(E, Result, &This);
9639 }
9640 bool VisitCastExpr(const CastExpr *E);
9641 bool VisitInitListExpr(const InitListExpr *E);
9642 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
9643 return VisitCXXConstructExpr(E, E->getType());
9644 }
9645 bool VisitLambdaExpr(const LambdaExpr *E);
9646 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
9647 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
9648 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
9649 bool VisitBinCmp(const BinaryOperator *E);
9650 };
9651}
9652
9653/// Perform zero-initialization on an object of non-union class type.
9654/// C++11 [dcl.init]p5:
9655/// To zero-initialize an object or reference of type T means:
9656/// [...]
9657/// -- if T is a (possibly cv-qualified) non-union class type,
9658/// each non-static data member and each base-class subobject is
9659/// zero-initialized
9660static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E,
9661 const RecordDecl *RD,
9662 const LValue &This, APValue &Result) {
9663 assert(!RD->isUnion() && "Expected non-union class type");
9664 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
9665 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0,
9666 std::distance(RD->field_begin(), RD->field_end()));
9667
9668 if (RD->isInvalidDecl()) return false;
9669 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9670
9671 if (CD) {
9672 unsigned Index = 0;
9673 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(),
9674 End = CD->bases_end(); I != End; ++I, ++Index) {
9675 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl();
9676 LValue Subobject = This;
9677 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout))
9678 return false;
9679 if (!HandleClassZeroInitialization(Info, E, Base, Subobject,
9680 Result.getStructBase(Index)))
9681 return false;
9682 }
9683 }
9684
9685 for (const auto *I : RD->fields()) {
9686 // -- if T is a reference type, no initialization is performed.
9687 if (I->isUnnamedBitfield() || I->getType()->isReferenceType())
9688 continue;
9689
9690 LValue Subobject = This;
9691 if (!HandleLValueMember(Info, E, Subobject, I, &Layout))
9692 return false;
9693
9694 ImplicitValueInitExpr VIE(I->getType());
9695 if (!EvaluateInPlace(
9696 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE))
9697 return false;
9698 }
9699
9700 return true;
9701}
9702
9703bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) {
9704 const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
9705 if (RD->isInvalidDecl()) return false;
9706 if (RD->isUnion()) {
9707 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the
9708 // object's first non-static named data member is zero-initialized
9709 RecordDecl::field_iterator I = RD->field_begin();
9710 while (I != RD->field_end() && (*I)->isUnnamedBitfield())
9711 ++I;
9712 if (I == RD->field_end()) {
9713 Result = APValue((const FieldDecl*)nullptr);
9714 return true;
9715 }
9716
9717 LValue Subobject = This;
9718 if (!HandleLValueMember(Info, E, Subobject, *I))
9719 return false;
9720 Result = APValue(*I);
9721 ImplicitValueInitExpr VIE(I->getType());
9722 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE);
9723 }
9724
9725 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) {
9726 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD;
9727 return false;
9728 }
9729
9730 return HandleClassZeroInitialization(Info, E, RD, This, Result);
9731}
9732
9733bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) {
9734 switch (E->getCastKind()) {
9735 default:
9736 return ExprEvaluatorBaseTy::VisitCastExpr(E);
9737
9738 case CK_ConstructorConversion:
9739 return Visit(E->getSubExpr());
9740
9741 case CK_DerivedToBase:
9742 case CK_UncheckedDerivedToBase: {
9743 APValue DerivedObject;
9744 if (!Evaluate(DerivedObject, Info, E->getSubExpr()))
9745 return false;
9746 if (!DerivedObject.isStruct())
9747 return Error(E->getSubExpr());
9748
9749 // Derived-to-base rvalue conversion: just slice off the derived part.
9750 APValue *Value = &DerivedObject;
9751 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl();
9752 for (CastExpr::path_const_iterator PathI = E->path_begin(),
9753 PathE = E->path_end(); PathI != PathE; ++PathI) {
9754 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base");
9755 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl();
9756 Value = &Value->getStructBase(getBaseIndex(RD, Base));
9757 RD = Base;
9758 }
9759 Result = *Value;
9760 return true;
9761 }
9762 }
9763}
9764
9765bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
9766 if (E->isTransparent())
9767 return Visit(E->getInit(0));
9768
9769 const RecordDecl *RD = E->getType()->castAs<RecordType>()->getDecl();
9770 if (RD->isInvalidDecl()) return false;
9771 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD);
9772 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
9773
9774 EvalInfo::EvaluatingConstructorRAII EvalObj(
9775 Info,
9776 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries},
9777 CXXRD && CXXRD->getNumBases());
9778
9779 if (RD->isUnion()) {
9780 const FieldDecl *Field = E->getInitializedFieldInUnion();
9781 Result = APValue(Field);
9782 if (!Field)
9783 return true;
9784
9785 // If the initializer list for a union does not contain any elements, the
9786 // first element of the union is value-initialized.
9787 // FIXME: The element should be initialized from an initializer list.
9788 // Is this difference ever observable for initializer lists which
9789 // we don't build?
9790 ImplicitValueInitExpr VIE(Field->getType());
9791 const Expr *InitExpr = E->getNumInits() ? E->getInit(0) : &VIE;
9792
9793 LValue Subobject = This;
9794 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout))
9795 return false;
9796
9797 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9798 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9799 isa<CXXDefaultInitExpr>(InitExpr));
9800
9801 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
9802 }
9803
9804 if (!Result.hasValue())
9805 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
9806 std::distance(RD->field_begin(), RD->field_end()));
9807 unsigned ElementNo = 0;
9808 bool Success = true;
9809
9810 // Initialize base classes.
9811 if (CXXRD && CXXRD->getNumBases()) {
9812 for (const auto &Base : CXXRD->bases()) {
9813 assert(ElementNo < E->getNumInits() && "missing init for base class");
9814 const Expr *Init = E->getInit(ElementNo);
9815
9816 LValue Subobject = This;
9817 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base))
9818 return false;
9819
9820 APValue &FieldVal = Result.getStructBase(ElementNo);
9821 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) {
9822 if (!Info.noteFailure())
9823 return false;
9824 Success = false;
9825 }
9826 ++ElementNo;
9827 }
9828
9829 EvalObj.finishedConstructingBases();
9830 }
9831
9832 // Initialize members.
9833 for (const auto *Field : RD->fields()) {
9834 // Anonymous bit-fields are not considered members of the class for
9835 // purposes of aggregate initialization.
9836 if (Field->isUnnamedBitfield())
9837 continue;
9838
9839 LValue Subobject = This;
9840
9841 bool HaveInit = ElementNo < E->getNumInits();
9842
9843 // FIXME: Diagnostics here should point to the end of the initializer
9844 // list, not the start.
9845 if (!HandleLValueMember(Info, HaveInit ? E->getInit(ElementNo) : E,
9846 Subobject, Field, &Layout))
9847 return false;
9848
9849 // Perform an implicit value-initialization for members beyond the end of
9850 // the initializer list.
9851 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType());
9852 const Expr *Init = HaveInit ? E->getInit(ElementNo++) : &VIE;
9853
9854 // Temporarily override This, in case there's a CXXDefaultInitExpr in here.
9855 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This,
9856 isa<CXXDefaultInitExpr>(Init));
9857
9858 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
9859 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) ||
9860 (Field->isBitField() && !truncateBitfieldValue(Info, Init,
9861 FieldVal, Field))) {
9862 if (!Info.noteFailure())
9863 return false;
9864 Success = false;
9865 }
9866 }
9867
9868 EvalObj.finishedConstructingFields();
9869
9870 return Success;
9871}
9872
9873bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
9874 QualType T) {
9875 // Note that E's type is not necessarily the type of our class here; we might
9876 // be initializing an array element instead.
9877 const CXXConstructorDecl *FD = E->getConstructor();
9878 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false;
9879
9880 bool ZeroInit = E->requiresZeroInitialization();
9881 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
9882 // If we've already performed zero-initialization, we're already done.
9883 if (Result.hasValue())
9884 return true;
9885
9886 if (ZeroInit)
9887 return ZeroInitialization(E, T);
9888
9889 return getDefaultInitValue(T, Result);
9890 }
9891
9892 const FunctionDecl *Definition = nullptr;
9893 auto Body = FD->getBody(Definition);
9894
9895 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9896 return false;
9897
9898 // Avoid materializing a temporary for an elidable copy/move constructor.
9899 if (E->isElidable() && !ZeroInit)
9900 if (const MaterializeTemporaryExpr *ME
9901 = dyn_cast<MaterializeTemporaryExpr>(E->getArg(0)))
9902 return Visit(ME->getSubExpr());
9903
9904 if (ZeroInit && !ZeroInitialization(E, T))
9905 return false;
9906
9907 auto Args = llvm::makeArrayRef(E->getArgs(), E->getNumArgs());
9908 return HandleConstructorCall(E, This, Args,
9909 cast<CXXConstructorDecl>(Definition), Info,
9910 Result);
9911}
9912
9913bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr(
9914 const CXXInheritedCtorInitExpr *E) {
9915 if (!Info.CurrentCall) {
9916 assert(Info.checkingPotentialConstantExpression());
9917 return false;
9918 }
9919
9920 const CXXConstructorDecl *FD = E->getConstructor();
9921 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl())
9922 return false;
9923
9924 const FunctionDecl *Definition = nullptr;
9925 auto Body = FD->getBody(Definition);
9926
9927 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
9928 return false;
9929
9930 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments,
9931 cast<CXXConstructorDecl>(Definition), Info,
9932 Result);
9933}
9934
9935bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
9936 const CXXStdInitializerListExpr *E) {
9937 const ConstantArrayType *ArrayType =
9938 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType());
9939
9940 LValue Array;
9941 if (!EvaluateLValue(E->getSubExpr(), Array, Info))
9942 return false;
9943
9944 // Get a pointer to the first element of the array.
9945 Array.addArray(Info, E, ArrayType);
9946
9947 auto InvalidType = [&] {
9948 Info.FFDiag(E, diag::note_constexpr_unsupported_layout)
9949 << E->getType();
9950 return false;
9951 };
9952
9953 // FIXME: Perform the checks on the field types in SemaInit.
9954 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl();
9955 RecordDecl::field_iterator Field = Record->field_begin();
9956 if (Field == Record->field_end())
9957 return InvalidType();
9958
9959 // Start pointer.
9960 if (!Field->getType()->isPointerType() ||
9961 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
9962 ArrayType->getElementType()))
9963 return InvalidType();
9964
9965 // FIXME: What if the initializer_list type has base classes, etc?
9966 Result = APValue(APValue::UninitStruct(), 0, 2);
9967 Array.moveInto(Result.getStructField(0));
9968
9969 if (++Field == Record->field_end())
9970 return InvalidType();
9971
9972 if (Field->getType()->isPointerType() &&
9973 Info.Ctx.hasSameType(Field->getType()->getPointeeType(),
9974 ArrayType->getElementType())) {
9975 // End pointer.
9976 if (!HandleLValueArrayAdjustment(Info, E, Array,
9977 ArrayType->getElementType(),
9978 ArrayType->getSize().getZExtValue()))
9979 return false;
9980 Array.moveInto(Result.getStructField(1));
9981 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType()))
9982 // Length.
9983 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize()));
9984 else
9985 return InvalidType();
9986
9987 if (++Field != Record->field_end())
9988 return InvalidType();
9989
9990 return true;
9991}
9992
9993bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
9994 const CXXRecordDecl *ClosureClass = E->getLambdaClass();
9995 if (ClosureClass->isInvalidDecl())
9996 return false;
9997
9998 const size_t NumFields =
9999 std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
10000
10001 assert(NumFields == (size_t)std::distance(E->capture_init_begin(),
10002 E->capture_init_end()) &&
10003 "The number of lambda capture initializers should equal the number of "
10004 "fields within the closure type");
10005
10006 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields);
10007 // Iterate through all the lambda's closure object's fields and initialize
10008 // them.
10009 auto *CaptureInitIt = E->capture_init_begin();
10010 const LambdaCapture *CaptureIt = ClosureClass->captures_begin();
10011 bool Success = true;
10012 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(ClosureClass);
10013 for (const auto *Field : ClosureClass->fields()) {
10014 assert(CaptureInitIt != E->capture_init_end());
10015 // Get the initializer for this field
10016 Expr *const CurFieldInit = *CaptureInitIt++;
10017
10018 // If there is no initializer, either this is a VLA or an error has
10019 // occurred.
10020 if (!CurFieldInit)
10021 return Error(E);
10022
10023 LValue Subobject = This;
10024
10025 if (!HandleLValueMember(Info, E, Subobject, Field, &Layout))
10026 return false;
10027
10028 APValue &FieldVal = Result.getStructField(Field->getFieldIndex());
10029 if (!EvaluateInPlace(FieldVal, Info, Subobject, CurFieldInit)) {
10030 if (!Info.keepEvaluatingAfterFailure())
10031 return false;
10032 Success = false;
10033 }
10034 ++CaptureIt;
10035 }
10036 return Success;
10037}
10038
10039static bool EvaluateRecord(const Expr *E, const LValue &This,
10040 APValue &Result, EvalInfo &Info) {
10041 assert(!E->isValueDependent());
10042 assert(E->isRValue() && E->getType()->isRecordType() &&
10043 "can't evaluate expression as a record rvalue");
10044 return RecordExprEvaluator(Info, This, Result).Visit(E);
10045}
10046
10047//===----------------------------------------------------------------------===//
10048// Temporary Evaluation
10049//
10050// Temporaries are represented in the AST as rvalues, but generally behave like
10051// lvalues. The full-object of which the temporary is a subobject is implicitly
10052// materialized so that a reference can bind to it.
10053//===----------------------------------------------------------------------===//
10054namespace {
10055class TemporaryExprEvaluator
10056 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> {
10057public:
10058 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) :
10059 LValueExprEvaluatorBaseTy(Info, Result, false) {}
10060
10061 /// Visit an expression which constructs the value of this temporary.
10062 bool VisitConstructExpr(const Expr *E) {
10063 APValue &Value = Info.CurrentCall->createTemporary(
10064 E, E->getType(), ScopeKind::FullExpression, Result);
10065 return EvaluateInPlace(Value, Info, Result, E);
10066 }
10067
10068 bool VisitCastExpr(const CastExpr *E) {
10069 switch (E->getCastKind()) {
10070 default:
10071 return LValueExprEvaluatorBaseTy::VisitCastExpr(E);
10072
10073 case CK_ConstructorConversion:
10074 return VisitConstructExpr(E->getSubExpr());
10075 }
10076 }
10077 bool VisitInitListExpr(const InitListExpr *E) {
10078 return VisitConstructExpr(E);
10079 }
10080 bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
10081 return VisitConstructExpr(E);
10082 }
10083 bool VisitCallExpr(const CallExpr *E) {
10084 return VisitConstructExpr(E);
10085 }
10086 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
10087 return VisitConstructExpr(E);
10088 }
10089 bool VisitLambdaExpr(const LambdaExpr *E) {
10090 return VisitConstructExpr(E);
10091 }
10092};
10093} // end anonymous namespace
10094
10095/// Evaluate an expression of record type as a temporary.
10096static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) {
10097 assert(!E->isValueDependent());
10098 assert(E->isRValue() && E->getType()->isRecordType());
10099 return TemporaryExprEvaluator(Info, Result).Visit(E);
10100}
10101
10102//===----------------------------------------------------------------------===//
10103// Vector Evaluation
10104//===----------------------------------------------------------------------===//
10105
10106namespace {
10107 class VectorExprEvaluator
10108 : public ExprEvaluatorBase<VectorExprEvaluator> {
10109 APValue &Result;
10110 public:
10111
10112 VectorExprEvaluator(EvalInfo &info, APValue &Result)
10113 : ExprEvaluatorBaseTy(info), Result(Result) {}
10114
10115 bool Success(ArrayRef<APValue> V, const Expr *E) {
10116 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements());
10117 // FIXME: remove this APValue copy.
10118 Result = APValue(V.data(), V.size());
10119 return true;
10120 }
10121 bool Success(const APValue &V, const Expr *E) {
10122 assert(V.isVector());
10123 Result = V;
10124 return true;
10125 }
10126 bool ZeroInitialization(const Expr *E);
10127
10128 bool VisitUnaryReal(const UnaryOperator *E)
10129 { return Visit(E->getSubExpr()); }
10130 bool VisitCastExpr(const CastExpr* E);
10131 bool VisitInitListExpr(const InitListExpr *E);
10132 bool VisitUnaryImag(const UnaryOperator *E);
10133 bool VisitBinaryOperator(const BinaryOperator *E);
10134 // FIXME: Missing: unary -, unary ~, conditional operator (for GNU
10135 // conditional select), shufflevector, ExtVectorElementExpr
10136 };
10137} // end anonymous namespace
10138
10139static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) {
10140 assert(E->isRValue() && E->getType()->isVectorType() &&"not a vector rvalue");
10141 return VectorExprEvaluator(Info, Result).Visit(E);
10142}
10143
10144bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) {
10145 const VectorType *VTy = E->getType()->castAs<VectorType>();
10146 unsigned NElts = VTy->getNumElements();
10147
10148 const Expr *SE = E->getSubExpr();
10149 QualType SETy = SE->getType();
10150
10151 switch (E->getCastKind()) {
10152 case CK_VectorSplat: {
10153 APValue Val = APValue();
10154 if (SETy->isIntegerType()) {
10155 APSInt IntResult;
10156 if (!EvaluateInteger(SE, IntResult, Info))
10157 return false;
10158 Val = APValue(std::move(IntResult));
10159 } else if (SETy->isRealFloatingType()) {
10160 APFloat FloatResult(0.0);
10161 if (!EvaluateFloat(SE, FloatResult, Info))
10162 return false;
10163 Val = APValue(std::move(FloatResult));
10164 } else {
10165 return Error(E);
10166 }
10167
10168 // Splat and create vector APValue.
10169 SmallVector<APValue, 4> Elts(NElts, Val);
10170 return Success(Elts, E);
10171 }
10172 case CK_BitCast: {
10173 // Evaluate the operand into an APInt we can extract from.
10174 llvm::APInt SValInt;
10175 if (!EvalAndBitcastToAPInt(Info, SE, SValInt))
10176 return false;
10177 // Extract the elements
10178 QualType EltTy = VTy->getElementType();
10179 unsigned EltSize = Info.Ctx.getTypeSize(EltTy);
10180 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian();
10181 SmallVector<APValue, 4> Elts;
10182 if (EltTy->isRealFloatingType()) {
10183 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy);
10184 unsigned FloatEltSize = EltSize;
10185 if (&Sem == &APFloat::x87DoubleExtended())
10186 FloatEltSize = 80;
10187 for (unsigned i = 0; i < NElts; i++) {
10188 llvm::APInt Elt;
10189 if (BigEndian)
10190 Elt = SValInt.rotl(i*EltSize+FloatEltSize).trunc(FloatEltSize);
10191 else
10192 Elt = SValInt.rotr(i*EltSize).trunc(FloatEltSize);
10193 Elts.push_back(APValue(APFloat(Sem, Elt)));
10194 }
10195 } else if (EltTy->isIntegerType()) {
10196 for (unsigned i = 0; i < NElts; i++) {
10197 llvm::APInt Elt;
10198 if (BigEndian)
10199 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize);
10200 else
10201 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize);
10202 Elts.push_back(APValue(APSInt(Elt, EltTy->isSignedIntegerType())));
10203 }
10204 } else {
10205 return Error(E);
10206 }
10207 return Success(Elts, E);
10208 }
10209 default:
10210 return ExprEvaluatorBaseTy::VisitCastExpr(E);
10211 }
10212}
10213
10214bool
10215VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
10216 const VectorType *VT = E->getType()->castAs<VectorType>();
10217 unsigned NumInits = E->getNumInits();
10218 unsigned NumElements = VT->getNumElements();
10219
10220 QualType EltTy = VT->getElementType();
10221 SmallVector<APValue, 4> Elements;
10222
10223 // The number of initializers can be less than the number of
10224 // vector elements. For OpenCL, this can be due to nested vector
10225 // initialization. For GCC compatibility, missing trailing elements
10226 // should be initialized with zeroes.
10227 unsigned CountInits = 0, CountElts = 0;
10228 while (CountElts < NumElements) {
10229 // Handle nested vector initialization.
10230 if (CountInits < NumInits
10231 && E->getInit(CountInits)->getType()->isVectorType()) {
10232 APValue v;
10233 if (!EvaluateVector(E->getInit(CountInits), v, Info))
10234 return Error(E);
10235 unsigned vlen = v.getVectorLength();
10236 for (unsigned j = 0; j < vlen; j++)
10237 Elements.push_back(v.getVectorElt(j));
10238 CountElts += vlen;
10239 } else if (EltTy->isIntegerType()) {
10240 llvm::APSInt sInt(32);
10241 if (CountInits < NumInits) {
10242 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info))
10243 return false;
10244 } else // trailing integer zero.
10245 sInt = Info.Ctx.MakeIntValue(0, EltTy);
10246 Elements.push_back(APValue(sInt));
10247 CountElts++;
10248 } else {
10249 llvm::APFloat f(0.0);
10250 if (CountInits < NumInits) {
10251 if (!EvaluateFloat(E->getInit(CountInits), f, Info))
10252 return false;
10253 } else // trailing float zero.
10254 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy));
10255 Elements.push_back(APValue(f));
10256 CountElts++;
10257 }
10258 CountInits++;
10259 }
10260 return Success(Elements, E);
10261}
10262
10263bool
10264VectorExprEvaluator::ZeroInitialization(const Expr *E) {
10265 const auto *VT = E->getType()->castAs<VectorType>();
10266 QualType EltTy = VT->getElementType();
10267 APValue ZeroElement;
10268 if (EltTy->isIntegerType())
10269 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy));
10270 else
10271 ZeroElement =
10272 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)));
10273
10274 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement);
10275 return Success(Elements, E);
10276}
10277
10278bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
10279 VisitIgnoredValue(E->getSubExpr());
10280 return ZeroInitialization(E);
10281}
10282
10283bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
10284 BinaryOperatorKind Op = E->getOpcode();
10285 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp &&
10286 "Operation not supported on vector types");
10287
10288 if (Op == BO_Comma)
10289 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
10290
10291 Expr *LHS = E->getLHS();
10292 Expr *RHS = E->getRHS();
10293
10294 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() &&
10295 "Must both be vector types");
10296 // Checking JUST the types are the same would be fine, except shifts don't
10297 // need to have their types be the same (since you always shift by an int).
10298 assert(LHS->getType()->getAs<VectorType>()->getNumElements() ==
10299 E->getType()->getAs<VectorType>()->getNumElements() &&
10300 RHS->getType()->getAs<VectorType>()->getNumElements() ==
10301 E->getType()->getAs<VectorType>()->getNumElements() &&
10302 "All operands must be the same size.");
10303
10304 APValue LHSValue;
10305 APValue RHSValue;
10306 bool LHSOK = Evaluate(LHSValue, Info, LHS);
10307 if (!LHSOK && !Info.noteFailure())
10308 return false;
10309 if (!Evaluate(RHSValue, Info, RHS) || !LHSOK)
10310 return false;
10311
10312 if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue))
10313 return false;
10314
10315 return Success(LHSValue, E);
10316}
10317
10318//===----------------------------------------------------------------------===//
10319// Array Evaluation
10320//===----------------------------------------------------------------------===//
10321
10322namespace {
10323 class ArrayExprEvaluator
10324 : public ExprEvaluatorBase<ArrayExprEvaluator> {
10325 const LValue &This;
10326 APValue &Result;
10327 public:
10328
10329 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result)
10330 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
10331
10332 bool Success(const APValue &V, const Expr *E) {
10333 assert(V.isArray() && "expected array");
10334 Result = V;
10335 return true;
10336 }
10337
10338 bool ZeroInitialization(const Expr *E) {
10339 const ConstantArrayType *CAT =
10340 Info.Ctx.getAsConstantArrayType(E->getType());
10341 if (!CAT) {
10342 if (E->getType()->isIncompleteArrayType()) {
10343 // We can be asked to zero-initialize a flexible array member; this
10344 // is represented as an ImplicitValueInitExpr of incomplete array
10345 // type. In this case, the array has zero elements.
10346 Result = APValue(APValue::UninitArray(), 0, 0);
10347 return true;
10348 }
10349 // FIXME: We could handle VLAs here.
10350 return Error(E);
10351 }
10352
10353 Result = APValue(APValue::UninitArray(), 0,
10354 CAT->getSize().getZExtValue());
10355 if (!Result.hasArrayFiller()) return true;
10356
10357 // Zero-initialize all elements.
10358 LValue Subobject = This;
10359 Subobject.addArray(Info, E, CAT);
10360 ImplicitValueInitExpr VIE(CAT->getElementType());
10361 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE);
10362 }
10363
10364 bool VisitCallExpr(const CallExpr *E) {
10365 return handleCallExpr(E, Result, &This);
10366 }
10367 bool VisitInitListExpr(const InitListExpr *E,
10368 QualType AllocType = QualType());
10369 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E);
10370 bool VisitCXXConstructExpr(const CXXConstructExpr *E);
10371 bool VisitCXXConstructExpr(const CXXConstructExpr *E,
10372 const LValue &Subobject,
10373 APValue *Value, QualType Type);
10374 bool VisitStringLiteral(const StringLiteral *E,
10375 QualType AllocType = QualType()) {
10376 expandStringLiteral(Info, E, Result, AllocType);
10377 return true;
10378 }
10379 };
10380} // end anonymous namespace
10381
10382static bool EvaluateArray(const Expr *E, const LValue &This,
10383 APValue &Result, EvalInfo &Info) {
10384 assert(!E->isValueDependent());
10385 assert(E->isRValue() && E->getType()->isArrayType() && "not an array rvalue");
10386 return ArrayExprEvaluator(Info, This, Result).Visit(E);
10387}
10388
10389static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This,
10390 APValue &Result, const InitListExpr *ILE,
10391 QualType AllocType) {
10392 assert(!ILE->isValueDependent());
10393 assert(ILE->isRValue() && ILE->getType()->isArrayType() &&
10394 "not an array rvalue");
10395 return ArrayExprEvaluator(Info, This, Result)
10396 .VisitInitListExpr(ILE, AllocType);
10397}
10398
10399static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This,
10400 APValue &Result,
10401 const CXXConstructExpr *CCE,
10402 QualType AllocType) {
10403 assert(!CCE->isValueDependent());
10404 assert(CCE->isRValue() && CCE->getType()->isArrayType() &&
10405 "not an array rvalue");
10406 return ArrayExprEvaluator(Info, This, Result)
10407 .VisitCXXConstructExpr(CCE, This, &Result, AllocType);
10408}
10409
10410// Return true iff the given array filler may depend on the element index.
10411static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) {
10412 // For now, just allow non-class value-initialization and initialization
10413 // lists comprised of them.
10414 if (isa<ImplicitValueInitExpr>(FillerExpr))
10415 return false;
10416 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) {
10417 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) {
10418 if (MaybeElementDependentArrayFiller(ILE->getInit(I)))
10419 return true;
10420 }
10421 return false;
10422 }
10423 return true;
10424}
10425
10426bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E,
10427 QualType AllocType) {
10428 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(
10429 AllocType.isNull() ? E->getType() : AllocType);
10430 if (!CAT)
10431 return Error(E);
10432
10433 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...]
10434 // an appropriately-typed string literal enclosed in braces.
10435 if (E->isStringLiteralInit()) {
10436 auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParens());
10437 // FIXME: Support ObjCEncodeExpr here once we support it in
10438 // ArrayExprEvaluator generally.
10439 if (!SL)
10440 return Error(E);
10441 return VisitStringLiteral(SL, AllocType);
10442 }
10443
10444 bool Success = true;
10445
10446 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) &&
10447 "zero-initialized array shouldn't have any initialized elts");
10448 APValue Filler;
10449 if (Result.isArray() && Result.hasArrayFiller())
10450 Filler = Result.getArrayFiller();
10451
10452 unsigned NumEltsToInit = E->getNumInits();
10453 unsigned NumElts = CAT->getSize().getZExtValue();
10454 const Expr *FillerExpr = E->hasArrayFiller() ? E->getArrayFiller() : nullptr;
10455
10456 // If the initializer might depend on the array index, run it for each
10457 // array element.
10458 if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(FillerExpr))
10459 NumEltsToInit = NumElts;
10460
10461 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: "
10462 << NumEltsToInit << ".\n");
10463
10464 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts);
10465
10466 // If the array was previously zero-initialized, preserve the
10467 // zero-initialized values.
10468 if (Filler.hasValue()) {
10469 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
10470 Result.getArrayInitializedElt(I) = Filler;
10471 if (Result.hasArrayFiller())
10472 Result.getArrayFiller() = Filler;
10473 }
10474
10475 LValue Subobject = This;
10476 Subobject.addArray(Info, E, CAT);
10477 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) {
10478 const Expr *Init =
10479 Index < E->getNumInits() ? E->getInit(Index) : FillerExpr;
10480 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10481 Info, Subobject, Init) ||
10482 !HandleLValueArrayAdjustment(Info, Init, Subobject,
10483 CAT->getElementType(), 1)) {
10484 if (!Info.noteFailure())
10485 return false;
10486 Success = false;
10487 }
10488 }
10489
10490 if (!Result.hasArrayFiller())
10491 return Success;
10492
10493 // If we get here, we have a trivial filler, which we can just evaluate
10494 // once and splat over the rest of the array elements.
10495 assert(FillerExpr && "no array filler for incomplete init list");
10496 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject,
10497 FillerExpr) && Success;
10498}
10499
10500bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) {
10501 LValue CommonLV;
10502 if (E->getCommonExpr() &&
10503 !Evaluate(Info.CurrentCall->createTemporary(
10504 E->getCommonExpr(),
10505 getStorageType(Info.Ctx, E->getCommonExpr()),
10506 ScopeKind::FullExpression, CommonLV),
10507 Info, E->getCommonExpr()->getSourceExpr()))
10508 return false;
10509
10510 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe());
10511
10512 uint64_t Elements = CAT->getSize().getZExtValue();
10513 Result = APValue(APValue::UninitArray(), Elements, Elements);
10514
10515 LValue Subobject = This;
10516 Subobject.addArray(Info, E, CAT);
10517
10518 bool Success = true;
10519 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) {
10520 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index),
10521 Info, Subobject, E->getSubExpr()) ||
10522 !HandleLValueArrayAdjustment(Info, E, Subobject,
10523 CAT->getElementType(), 1)) {
10524 if (!Info.noteFailure())
10525 return false;
10526 Success = false;
10527 }
10528 }
10529
10530 return Success;
10531}
10532
10533bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
10534 return VisitCXXConstructExpr(E, This, &Result, E->getType());
10535}
10536
10537bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
10538 const LValue &Subobject,
10539 APValue *Value,
10540 QualType Type) {
10541 bool HadZeroInit = Value->hasValue();
10542
10543 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
10544 unsigned N = CAT->getSize().getZExtValue();
10545
10546 // Preserve the array filler if we had prior zero-initialization.
10547 APValue Filler =
10548 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller()
10549 : APValue();
10550
10551 *Value = APValue(APValue::UninitArray(), N, N);
10552
10553 if (HadZeroInit)
10554 for (unsigned I = 0; I != N; ++I)
10555 Value->getArrayInitializedElt(I) = Filler;
10556
10557 // Initialize the elements.
10558 LValue ArrayElt = Subobject;
10559 ArrayElt.addArray(Info, E, CAT);
10560 for (unsigned I = 0; I != N; ++I)
10561 if (!VisitCXXConstructExpr(E, ArrayElt, &Value->getArrayInitializedElt(I),
10562 CAT->getElementType()) ||
10563 !HandleLValueArrayAdjustment(Info, E, ArrayElt,
10564 CAT->getElementType(), 1))
10565 return false;
10566
10567 return true;
10568 }
10569
10570 if (!Type->isRecordType())
10571 return Error(E);
10572
10573 return RecordExprEvaluator(Info, Subobject, *Value)
10574 .VisitCXXConstructExpr(E, Type);
10575}
10576
10577//===----------------------------------------------------------------------===//
10578// Integer Evaluation
10579//
10580// As a GNU extension, we support casting pointers to sufficiently-wide integer
10581// types and back in constant folding. Integer values are thus represented
10582// either as an integer-valued APValue, or as an lvalue-valued APValue.
10583//===----------------------------------------------------------------------===//
10584
10585namespace {
10586class IntExprEvaluator
10587 : public ExprEvaluatorBase<IntExprEvaluator> {
10588 APValue &Result;
10589public:
10590 IntExprEvaluator(EvalInfo &info, APValue &result)
10591 : ExprEvaluatorBaseTy(info), Result(result) {}
10592
10593 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) {
10594 assert(E->getType()->isIntegralOrEnumerationType() &&
10595 "Invalid evaluation result.");
10596 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() &&
10597 "Invalid evaluation result.");
10598 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10599 "Invalid evaluation result.");
10600 Result = APValue(SI);
10601 return true;
10602 }
10603 bool Success(const llvm::APSInt &SI, const Expr *E) {
10604 return Success(SI, E, Result);
10605 }
10606
10607 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
10608 assert(E->getType()->isIntegralOrEnumerationType() &&
10609 "Invalid evaluation result.");
10610 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10611 "Invalid evaluation result.");
10612 Result = APValue(APSInt(I));
10613 Result.getInt().setIsUnsigned(
10614 E->getType()->isUnsignedIntegerOrEnumerationType());
10615 return true;
10616 }
10617 bool Success(const llvm::APInt &I, const Expr *E) {
10618 return Success(I, E, Result);
10619 }
10620
10621 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
10622 assert(E->getType()->isIntegralOrEnumerationType() &&
10623 "Invalid evaluation result.");
10624 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
10625 return true;
10626 }
10627 bool Success(uint64_t Value, const Expr *E) {
10628 return Success(Value, E, Result);
10629 }
10630
10631 bool Success(CharUnits Size, const Expr *E) {
10632 return Success(Size.getQuantity(), E);
10633 }
10634
10635 bool Success(const APValue &V, const Expr *E) {
10636 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) {
10637 Result = V;
10638 return true;
10639 }
10640 return Success(V.getInt(), E);
10641 }
10642
10643 bool ZeroInitialization(const Expr *E) { return Success(0, E); }
10644
10645 //===--------------------------------------------------------------------===//
10646 // Visitor Methods
10647 //===--------------------------------------------------------------------===//
10648
10649 bool VisitIntegerLiteral(const IntegerLiteral *E) {
10650 return Success(E->getValue(), E);
10651 }
10652 bool VisitCharacterLiteral(const CharacterLiteral *E) {
10653 return Success(E->getValue(), E);
10654 }
10655
10656 bool CheckReferencedDecl(const Expr *E, const Decl *D);
10657 bool VisitDeclRefExpr(const DeclRefExpr *E) {
10658 if (CheckReferencedDecl(E, E->getDecl()))
10659 return true;
10660
10661 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E);
10662 }
10663 bool VisitMemberExpr(const MemberExpr *E) {
10664 if (CheckReferencedDecl(E, E->getMemberDecl())) {
10665 VisitIgnoredBaseExpression(E->getBase());
10666 return true;
10667 }
10668
10669 return ExprEvaluatorBaseTy::VisitMemberExpr(E);
10670 }
10671
10672 bool VisitCallExpr(const CallExpr *E);
10673 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp);
10674 bool VisitBinaryOperator(const BinaryOperator *E);
10675 bool VisitOffsetOfExpr(const OffsetOfExpr *E);
10676 bool VisitUnaryOperator(const UnaryOperator *E);
10677
10678 bool VisitCastExpr(const CastExpr* E);
10679 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E);
10680
10681 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) {
10682 return Success(E->getValue(), E);
10683 }
10684
10685 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) {
10686 return Success(E->getValue(), E);
10687 }
10688
10689 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) {
10690 if (Info.ArrayInitIndex == uint64_t(-1)) {
10691 // We were asked to evaluate this subexpression independent of the
10692 // enclosing ArrayInitLoopExpr. We can't do that.
10693 Info.FFDiag(E);
10694 return false;
10695 }
10696 return Success(Info.ArrayInitIndex, E);
10697 }
10698
10699 // Note, GNU defines __null as an integer, not a pointer.
10700 bool VisitGNUNullExpr(const GNUNullExpr *E) {
10701 return ZeroInitialization(E);
10702 }
10703
10704 bool VisitTypeTraitExpr(const TypeTraitExpr *E) {
10705 return Success(E->getValue(), E);
10706 }
10707
10708 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) {
10709 return Success(E->getValue(), E);
10710 }
10711
10712 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) {
10713 return Success(E->getValue(), E);
10714 }
10715
10716 bool VisitUnaryReal(const UnaryOperator *E);
10717 bool VisitUnaryImag(const UnaryOperator *E);
10718
10719 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E);
10720 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E);
10721 bool VisitSourceLocExpr(const SourceLocExpr *E);
10722 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
10723 bool VisitRequiresExpr(const RequiresExpr *E);
10724 // FIXME: Missing: array subscript of vector, member of vector
10725};
10726
10727class FixedPointExprEvaluator
10728 : public ExprEvaluatorBase<FixedPointExprEvaluator> {
10729 APValue &Result;
10730
10731 public:
10732 FixedPointExprEvaluator(EvalInfo &info, APValue &result)
10733 : ExprEvaluatorBaseTy(info), Result(result) {}
10734
10735 bool Success(const llvm::APInt &I, const Expr *E) {
10736 return Success(
10737 APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10738 }
10739
10740 bool Success(uint64_t Value, const Expr *E) {
10741 return Success(
10742 APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E);
10743 }
10744
10745 bool Success(const APValue &V, const Expr *E) {
10746 return Success(V.getFixedPoint(), E);
10747 }
10748
10749 bool Success(const APFixedPoint &V, const Expr *E) {
10750 assert(E->getType()->isFixedPointType() && "Invalid evaluation result.");
10751 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) &&
10752 "Invalid evaluation result.");
10753 Result = APValue(V);
10754 return true;
10755 }
10756
10757 //===--------------------------------------------------------------------===//
10758 // Visitor Methods
10759 //===--------------------------------------------------------------------===//
10760
10761 bool VisitFixedPointLiteral(const FixedPointLiteral *E) {
10762 return Success(E->getValue(), E);
10763 }
10764
10765 bool VisitCastExpr(const CastExpr *E);
10766 bool VisitUnaryOperator(const UnaryOperator *E);
10767 bool VisitBinaryOperator(const BinaryOperator *E);
10768};
10769} // end anonymous namespace
10770
10771/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and
10772/// produce either the integer value or a pointer.
10773///
10774/// GCC has a heinous extension which folds casts between pointer types and
10775/// pointer-sized integral types. We support this by allowing the evaluation of
10776/// an integer rvalue to produce a pointer (represented as an lvalue) instead.
10777/// Some simple arithmetic on such values is supported (they are treated much
10778/// like char*).
10779static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
10780 EvalInfo &Info) {
10781 assert(!E->isValueDependent());
10782 assert(E->isRValue() && E->getType()->isIntegralOrEnumerationType());
10783 return IntExprEvaluator(Info, Result).Visit(E);
10784}
10785
10786static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) {
10787 assert(!E->isValueDependent());
10788 APValue Val;
10789 if (!EvaluateIntegerOrLValue(E, Val, Info))
10790 return false;
10791 if (!Val.isInt()) {
10792 // FIXME: It would be better to produce the diagnostic for casting
10793 // a pointer to an integer.
10794 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
10795 return false;
10796 }
10797 Result = Val.getInt();
10798 return true;
10799}
10800
10801bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) {
10802 APValue Evaluated = E->EvaluateInContext(
10803 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr());
10804 return Success(Evaluated, E);
10805}
10806
10807static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result,
10808 EvalInfo &Info) {
10809 assert(!E->isValueDependent());
10810 if (E->getType()->isFixedPointType()) {
10811 APValue Val;
10812 if (!FixedPointExprEvaluator(Info, Val).Visit(E))
10813 return false;
10814 if (!Val.isFixedPoint())
10815 return false;
10816
10817 Result = Val.getFixedPoint();
10818 return true;
10819 }
10820 return false;
10821}
10822
10823static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result,
10824 EvalInfo &Info) {
10825 assert(!E->isValueDependent());
10826 if (E->getType()->isIntegerType()) {
10827 auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType());
10828 APSInt Val;
10829 if (!EvaluateInteger(E, Val, Info))
10830 return false;
10831 Result = APFixedPoint(Val, FXSema);
10832 return true;
10833 } else if (E->getType()->isFixedPointType()) {
10834 return EvaluateFixedPoint(E, Result, Info);
10835 }
10836 return false;
10837}
10838
10839/// Check whether the given declaration can be directly converted to an integral
10840/// rvalue. If not, no diagnostic is produced; there are other things we can
10841/// try.
10842bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) {
10843 // Enums are integer constant exprs.
10844 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) {
10845 // Check for signedness/width mismatches between E type and ECD value.
10846 bool SameSign = (ECD->getInitVal().isSigned()
10847 == E->getType()->isSignedIntegerOrEnumerationType());
10848 bool SameWidth = (ECD->getInitVal().getBitWidth()
10849 == Info.Ctx.getIntWidth(E->getType()));
10850 if (SameSign && SameWidth)
10851 return Success(ECD->getInitVal(), E);
10852 else {
10853 // Get rid of mismatch (otherwise Success assertions will fail)
10854 // by computing a new value matching the type of E.
10855 llvm::APSInt Val = ECD->getInitVal();
10856 if (!SameSign)
10857 Val.setIsSigned(!ECD->getInitVal().isSigned());
10858 if (!SameWidth)
10859 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
10860 return Success(Val, E);
10861 }
10862 }
10863 return false;
10864}
10865
10866/// Values returned by __builtin_classify_type, chosen to match the values
10867/// produced by GCC's builtin.
10868enum class GCCTypeClass {
10869 None = -1,
10870 Void = 0,
10871 Integer = 1,
10872 // GCC reserves 2 for character types, but instead classifies them as
10873 // integers.
10874 Enum = 3,
10875 Bool = 4,
10876 Pointer = 5,
10877 // GCC reserves 6 for references, but appears to never use it (because
10878 // expressions never have reference type, presumably).
10879 PointerToDataMember = 7,
10880 RealFloat = 8,
10881 Complex = 9,
10882 // GCC reserves 10 for functions, but does not use it since GCC version 6 due
10883 // to decay to pointer. (Prior to version 6 it was only used in C++ mode).
10884 // GCC claims to reserve 11 for pointers to member functions, but *actually*
10885 // uses 12 for that purpose, same as for a class or struct. Maybe it
10886 // internally implements a pointer to member as a struct? Who knows.
10887 PointerToMemberFunction = 12, // Not a bug, see above.
10888 ClassOrStruct = 12,
10889 Union = 13,
10890 // GCC reserves 14 for arrays, but does not use it since GCC version 6 due to
10891 // decay to pointer. (Prior to version 6 it was only used in C++ mode).
10892 // GCC reserves 15 for strings, but actually uses 5 (pointer) for string
10893 // literals.
10894};
10895
10896/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
10897/// as GCC.
10898static GCCTypeClass
10899EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) {
10900 assert(!T->isDependentType() && "unexpected dependent type");
10901
10902 QualType CanTy = T.getCanonicalType();
10903 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy);
10904
10905 switch (CanTy->getTypeClass()) {
10906#define TYPE(ID, BASE)
10907#define DEPENDENT_TYPE(ID, BASE) case Type::ID:
10908#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID:
10909#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID:
10910#include "clang/AST/TypeNodes.inc"
10911 case Type::Auto:
10912 case Type::DeducedTemplateSpecialization:
10913 llvm_unreachable("unexpected non-canonical or dependent type");
10914
10915 case Type::Builtin:
10916 switch (BT->getKind()) {
10917#define BUILTIN_TYPE(ID, SINGLETON_ID)
10918#define SIGNED_TYPE(ID, SINGLETON_ID) \
10919 case BuiltinType::ID: return GCCTypeClass::Integer;
10920#define FLOATING_TYPE(ID, SINGLETON_ID) \
10921 case BuiltinType::ID: return GCCTypeClass::RealFloat;
10922#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \
10923 case BuiltinType::ID: break;
10924#include "clang/AST/BuiltinTypes.def"
10925 case BuiltinType::Void:
10926 return GCCTypeClass::Void;
10927
10928 case BuiltinType::Bool:
10929 return GCCTypeClass::Bool;
10930
10931 case BuiltinType::Char_U:
10932 case BuiltinType::UChar:
10933 case BuiltinType::WChar_U:
10934 case BuiltinType::Char8:
10935 case BuiltinType::Char16:
10936 case BuiltinType::Char32:
10937 case BuiltinType::UShort:
10938 case BuiltinType::UInt:
10939 case BuiltinType::ULong:
10940 case BuiltinType::ULongLong:
10941 case BuiltinType::UInt128:
10942 return GCCTypeClass::Integer;
10943
10944 case BuiltinType::UShortAccum:
10945 case BuiltinType::UAccum:
10946 case BuiltinType::ULongAccum:
10947 case BuiltinType::UShortFract:
10948 case BuiltinType::UFract:
10949 case BuiltinType::ULongFract:
10950 case BuiltinType::SatUShortAccum:
10951 case BuiltinType::SatUAccum:
10952 case BuiltinType::SatULongAccum:
10953 case BuiltinType::SatUShortFract:
10954 case BuiltinType::SatUFract:
10955 case BuiltinType::SatULongFract:
10956 return GCCTypeClass::None;
10957
10958 case BuiltinType::NullPtr:
10959
10960 case BuiltinType::ObjCId:
10961 case BuiltinType::ObjCClass:
10962 case BuiltinType::ObjCSel:
10963#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
10964 case BuiltinType::Id:
10965#include "clang/Basic/OpenCLImageTypes.def"
10966#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
10967 case BuiltinType::Id:
10968#include "clang/Basic/OpenCLExtensionTypes.def"
10969 case BuiltinType::OCLSampler:
10970 case BuiltinType::OCLEvent:
10971 case BuiltinType::OCLClkEvent:
10972 case BuiltinType::OCLQueue:
10973 case BuiltinType::OCLReserveID:
10974#define SVE_TYPE(Name, Id, SingletonId) \
10975 case BuiltinType::Id:
10976#include "clang/Basic/AArch64SVEACLETypes.def"
10977#define PPC_VECTOR_TYPE(Name, Id, Size) \
10978 case BuiltinType::Id:
10979#include "clang/Basic/PPCTypes.def"
10980 return GCCTypeClass::None;
10981
10982 case BuiltinType::Dependent:
10983 llvm_unreachable("unexpected dependent type");
10984 };
10985 llvm_unreachable("unexpected placeholder type");
10986
10987 case Type::Enum:
10988 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer;
10989
10990 case Type::Pointer:
10991 case Type::ConstantArray:
10992 case Type::VariableArray:
10993 case Type::IncompleteArray:
10994 case Type::FunctionNoProto:
10995 case Type::FunctionProto:
10996 return GCCTypeClass::Pointer;
10997
10998 case Type::MemberPointer:
10999 return CanTy->isMemberDataPointerType()
11000 ? GCCTypeClass::PointerToDataMember
11001 : GCCTypeClass::PointerToMemberFunction;
11002
11003 case Type::Complex:
11004 return GCCTypeClass::Complex;
11005
11006 case Type::Record:
11007 return CanTy->isUnionType() ? GCCTypeClass::Union
11008 : GCCTypeClass::ClassOrStruct;
11009
11010 case Type::Atomic:
11011 // GCC classifies _Atomic T the same as T.
11012 return EvaluateBuiltinClassifyType(
11013 CanTy->castAs<AtomicType>()->getValueType(), LangOpts);
11014
11015 case Type::BlockPointer:
11016 case Type::Vector:
11017 case Type::ExtVector:
11018 case Type::ConstantMatrix:
11019 case Type::ObjCObject:
11020 case Type::ObjCInterface:
11021 case Type::ObjCObjectPointer:
11022 case Type::Pipe:
11023 case Type::ExtInt:
11024 // GCC classifies vectors as None. We follow its lead and classify all
11025 // other types that don't fit into the regular classification the same way.
11026 return GCCTypeClass::None;
11027
11028 case Type::LValueReference:
11029 case Type::RValueReference:
11030 llvm_unreachable("invalid type for expression");
11031 }
11032
11033 llvm_unreachable("unexpected type class");
11034}
11035
11036/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way
11037/// as GCC.
11038static GCCTypeClass
11039EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) {
11040 // If no argument was supplied, default to None. This isn't
11041 // ideal, however it is what gcc does.
11042 if (E->getNumArgs() == 0)
11043 return GCCTypeClass::None;
11044
11045 // FIXME: Bizarrely, GCC treats a call with more than one argument as not
11046 // being an ICE, but still folds it to a constant using the type of the first
11047 // argument.
11048 return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts);
11049}
11050
11051/// EvaluateBuiltinConstantPForLValue - Determine the result of
11052/// __builtin_constant_p when applied to the given pointer.
11053///
11054/// A pointer is only "constant" if it is null (or a pointer cast to integer)
11055/// or it points to the first character of a string literal.
11056static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) {
11057 APValue::LValueBase Base = LV.getLValueBase();
11058 if (Base.isNull()) {
11059 // A null base is acceptable.
11060 return true;
11061 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) {
11062 if (!isa<StringLiteral>(E))
11063 return false;
11064 return LV.getLValueOffset().isZero();
11065 } else if (Base.is<TypeInfoLValue>()) {
11066 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to
11067 // evaluate to true.
11068 return true;
11069 } else {
11070 // Any other base is not constant enough for GCC.
11071 return false;
11072 }
11073}
11074
11075/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to
11076/// GCC as we can manage.
11077static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) {
11078 // This evaluation is not permitted to have side-effects, so evaluate it in
11079 // a speculative evaluation context.
11080 SpeculativeEvaluationRAII SpeculativeEval(Info);
11081
11082 // Constant-folding is always enabled for the operand of __builtin_constant_p
11083 // (even when the enclosing evaluation context otherwise requires a strict
11084 // language-specific constant expression).
11085 FoldConstant Fold(Info, true);
11086
11087 QualType ArgType = Arg->getType();
11088
11089 // __builtin_constant_p always has one operand. The rules which gcc follows
11090 // are not precisely documented, but are as follows:
11091 //
11092 // - If the operand is of integral, floating, complex or enumeration type,
11093 // and can be folded to a known value of that type, it returns 1.
11094 // - If the operand can be folded to a pointer to the first character
11095 // of a string literal (or such a pointer cast to an integral type)
11096 // or to a null pointer or an integer cast to a pointer, it returns 1.
11097 //
11098 // Otherwise, it returns 0.
11099 //
11100 // FIXME: GCC also intends to return 1 for literals of aggregate types, but
11101 // its support for this did not work prior to GCC 9 and is not yet well
11102 // understood.
11103 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() ||
11104 ArgType->isAnyComplexType() || ArgType->isPointerType() ||
11105 ArgType->isNullPtrType()) {
11106 APValue V;
11107 if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) {
11108 Fold.keepDiagnostics();
11109 return false;
11110 }
11111
11112 // For a pointer (possibly cast to integer), there are special rules.
11113 if (V.getKind() == APValue::LValue)
11114 return EvaluateBuiltinConstantPForLValue(V);
11115
11116 // Otherwise, any constant value is good enough.
11117 return V.hasValue();
11118 }
11119
11120 // Anything else isn't considered to be sufficiently constant.
11121 return false;
11122}
11123
11124/// Retrieves the "underlying object type" of the given expression,
11125/// as used by __builtin_object_size.
11126static QualType getObjectType(APValue::LValueBase B) {
11127 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) {
11128 if (const VarDecl *VD = dyn_cast<VarDecl>(D))
11129 return VD->getType();
11130 } else if (const Expr *E = B.dyn_cast<const Expr*>()) {
11131 if (isa<CompoundLiteralExpr>(E))
11132 return E->getType();
11133 } else if (B.is<TypeInfoLValue>()) {
11134 return B.getTypeInfoType();
11135 } else if (B.is<DynamicAllocLValue>()) {
11136 return B.getDynamicAllocType();
11137 }
11138
11139 return QualType();
11140}
11141
11142/// A more selective version of E->IgnoreParenCasts for
11143/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only
11144/// to change the type of E.
11145/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo`
11146///
11147/// Always returns an RValue with a pointer representation.
11148static const Expr *ignorePointerCastsAndParens(const Expr *E) {
11149 assert(E->isRValue() && E->getType()->hasPointerRepresentation());
11150
11151 auto *NoParens = E->IgnoreParens();
11152 auto *Cast = dyn_cast<CastExpr>(NoParens);
11153 if (Cast == nullptr)
11154 return NoParens;
11155
11156 // We only conservatively allow a few kinds of casts, because this code is
11157 // inherently a simple solution that seeks to support the common case.
11158 auto CastKind = Cast->getCastKind();
11159 if (CastKind != CK_NoOp && CastKind != CK_BitCast &&
11160 CastKind != CK_AddressSpaceConversion)
11161 return NoParens;
11162
11163 auto *SubExpr = Cast->getSubExpr();
11164 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isRValue())
11165 return NoParens;
11166 return ignorePointerCastsAndParens(SubExpr);
11167}
11168
11169/// Checks to see if the given LValue's Designator is at the end of the LValue's
11170/// record layout. e.g.
11171/// struct { struct { int a, b; } fst, snd; } obj;
11172/// obj.fst // no
11173/// obj.snd // yes
11174/// obj.fst.a // no
11175/// obj.fst.b // no
11176/// obj.snd.a // no
11177/// obj.snd.b // yes
11178///
11179/// Please note: this function is specialized for how __builtin_object_size
11180/// views "objects".
11181///
11182/// If this encounters an invalid RecordDecl or otherwise cannot determine the
11183/// correct result, it will always return true.
11184static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) {
11185 assert(!LVal.Designator.Invalid);
11186
11187 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) {
11188 const RecordDecl *Parent = FD->getParent();
11189 Invalid = Parent->isInvalidDecl();
11190 if (Invalid || Parent->isUnion())
11191 return true;
11192 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent);
11193 return FD->getFieldIndex() + 1 == Layout.getFieldCount();
11194 };
11195
11196 auto &Base = LVal.getLValueBase();
11197 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) {
11198 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
11199 bool Invalid;
11200 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11201 return Invalid;
11202 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) {
11203 for (auto *FD : IFD->chain()) {
11204 bool Invalid;
11205 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid))
11206 return Invalid;
11207 }
11208 }
11209 }
11210
11211 unsigned I = 0;
11212 QualType BaseType = getType(Base);
11213 if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
11214 // If we don't know the array bound, conservatively assume we're looking at
11215 // the final array element.
11216 ++I;
11217 if (BaseType->isIncompleteArrayType())
11218 BaseType = Ctx.getAsArrayType(BaseType)->getElementType();
11219 else
11220 BaseType = BaseType->castAs<PointerType>()->getPointeeType();
11221 }
11222
11223 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) {
11224 const auto &Entry = LVal.Designator.Entries[I];
11225 if (BaseType->isArrayType()) {
11226 // Because __builtin_object_size treats arrays as objects, we can ignore
11227 // the index iff this is the last array in the Designator.
11228 if (I + 1 == E)
11229 return true;
11230 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType));
11231 uint64_t Index = Entry.getAsArrayIndex();
11232 if (Index + 1 != CAT->getSize())
11233 return false;
11234 BaseType = CAT->getElementType();
11235 } else if (BaseType->isAnyComplexType()) {
11236 const auto *CT = BaseType->castAs<ComplexType>();
11237 uint64_t Index = Entry.getAsArrayIndex();
11238 if (Index != 1)
11239 return false;
11240 BaseType = CT->getElementType();
11241 } else if (auto *FD = getAsField(Entry)) {
11242 bool Invalid;
11243 if (!IsLastOrInvalidFieldDecl(FD, Invalid))
11244 return Invalid;
11245 BaseType = FD->getType();
11246 } else {
11247 assert(getAsBaseClass(Entry) && "Expecting cast to a base class");
11248 return false;
11249 }
11250 }
11251 return true;
11252}
11253
11254/// Tests to see if the LValue has a user-specified designator (that isn't
11255/// necessarily valid). Note that this always returns 'true' if the LValue has
11256/// an unsized array as its first designator entry, because there's currently no
11257/// way to tell if the user typed *foo or foo[0].
11258static bool refersToCompleteObject(const LValue &LVal) {
11259 if (LVal.Designator.Invalid)
11260 return false;
11261
11262 if (!LVal.Designator.Entries.empty())
11263 return LVal.Designator.isMostDerivedAnUnsizedArray();
11264
11265 if (!LVal.InvalidBase)
11266 return true;
11267
11268 // If `E` is a MemberExpr, then the first part of the designator is hiding in
11269 // the LValueBase.
11270 const auto *E = LVal.Base.dyn_cast<const Expr *>();
11271 return !E || !isa<MemberExpr>(E);
11272}
11273
11274/// Attempts to detect a user writing into a piece of memory that's impossible
11275/// to figure out the size of by just using types.
11276static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) {
11277 const SubobjectDesignator &Designator = LVal.Designator;
11278 // Notes:
11279 // - Users can only write off of the end when we have an invalid base. Invalid
11280 // bases imply we don't know where the memory came from.
11281 // - We used to be a bit more aggressive here; we'd only be conservative if
11282 // the array at the end was flexible, or if it had 0 or 1 elements. This
11283 // broke some common standard library extensions (PR30346), but was
11284 // otherwise seemingly fine. It may be useful to reintroduce this behavior
11285 // with some sort of list. OTOH, it seems that GCC is always
11286 // conservative with the last element in structs (if it's an array), so our
11287 // current behavior is more compatible than an explicit list approach would
11288 // be.
11289 return LVal.InvalidBase &&
11290 Designator.Entries.size() == Designator.MostDerivedPathLength &&
11291 Designator.MostDerivedIsArrayElement &&
11292 isDesignatorAtObjectEnd(Ctx, LVal);
11293}
11294
11295/// Converts the given APInt to CharUnits, assuming the APInt is unsigned.
11296/// Fails if the conversion would cause loss of precision.
11297static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int,
11298 CharUnits &Result) {
11299 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max();
11300 if (Int.ugt(CharUnitsMax))
11301 return false;
11302 Result = CharUnits::fromQuantity(Int.getZExtValue());
11303 return true;
11304}
11305
11306/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will
11307/// determine how many bytes exist from the beginning of the object to either
11308/// the end of the current subobject, or the end of the object itself, depending
11309/// on what the LValue looks like + the value of Type.
11310///
11311/// If this returns false, the value of Result is undefined.
11312static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc,
11313 unsigned Type, const LValue &LVal,
11314 CharUnits &EndOffset) {
11315 bool DetermineForCompleteObject = refersToCompleteObject(LVal);
11316
11317 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) {
11318 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType())
11319 return false;
11320 return HandleSizeof(Info, ExprLoc, Ty, Result);
11321 };
11322
11323 // We want to evaluate the size of the entire object. This is a valid fallback
11324 // for when Type=1 and the designator is invalid, because we're asked for an
11325 // upper-bound.
11326 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) {
11327 // Type=3 wants a lower bound, so we can't fall back to this.
11328 if (Type == 3 && !DetermineForCompleteObject)
11329 return false;
11330
11331 llvm::APInt APEndOffset;
11332 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
11333 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
11334 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
11335
11336 if (LVal.InvalidBase)
11337 return false;
11338
11339 QualType BaseTy = getObjectType(LVal.getLValueBase());
11340 return CheckedHandleSizeof(BaseTy, EndOffset);
11341 }
11342
11343 // We want to evaluate the size of a subobject.
11344 const SubobjectDesignator &Designator = LVal.Designator;
11345
11346 // The following is a moderately common idiom in C:
11347 //
11348 // struct Foo { int a; char c[1]; };
11349 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar));
11350 // strcpy(&F->c[0], Bar);
11351 //
11352 // In order to not break too much legacy code, we need to support it.
11353 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) {
11354 // If we can resolve this to an alloc_size call, we can hand that back,
11355 // because we know for certain how many bytes there are to write to.
11356 llvm::APInt APEndOffset;
11357 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) &&
11358 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset))
11359 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset);
11360
11361 // If we cannot determine the size of the initial allocation, then we can't
11362 // given an accurate upper-bound. However, we are still able to give
11363 // conservative lower-bounds for Type=3.
11364 if (Type == 1)
11365 return false;
11366 }
11367
11368 CharUnits BytesPerElem;
11369 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem))
11370 return false;
11371
11372 // According to the GCC documentation, we want the size of the subobject
11373 // denoted by the pointer. But that's not quite right -- what we actually
11374 // want is the size of the immediately-enclosing array, if there is one.
11375 int64_t ElemsRemaining;
11376 if (Designator.MostDerivedIsArrayElement &&
11377 Designator.Entries.size() == Designator.MostDerivedPathLength) {
11378 uint64_t ArraySize = Designator.getMostDerivedArraySize();
11379 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex();
11380 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex;
11381 } else {
11382 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1;
11383 }
11384
11385 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining;
11386 return true;
11387}
11388
11389/// Tries to evaluate the __builtin_object_size for @p E. If successful,
11390/// returns true and stores the result in @p Size.
11391///
11392/// If @p WasError is non-null, this will report whether the failure to evaluate
11393/// is to be treated as an Error in IntExprEvaluator.
11394static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type,
11395 EvalInfo &Info, uint64_t &Size) {
11396 // Determine the denoted object.
11397 LValue LVal;
11398 {
11399 // The operand of __builtin_object_size is never evaluated for side-effects.
11400 // If there are any, but we can determine the pointed-to object anyway, then
11401 // ignore the side-effects.
11402 SpeculativeEvaluationRAII SpeculativeEval(Info);
11403 IgnoreSideEffectsRAII Fold(Info);
11404
11405 if (E->isGLValue()) {
11406 // It's possible for us to be given GLValues if we're called via
11407 // Expr::tryEvaluateObjectSize.
11408 APValue RVal;
11409 if (!EvaluateAsRValue(Info, E, RVal))
11410 return false;
11411 LVal.setFrom(Info.Ctx, RVal);
11412 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info,
11413 /*InvalidBaseOK=*/true))
11414 return false;
11415 }
11416
11417 // If we point to before the start of the object, there are no accessible
11418 // bytes.
11419 if (LVal.getLValueOffset().isNegative()) {
11420 Size = 0;
11421 return true;
11422 }
11423
11424 CharUnits EndOffset;
11425 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset))
11426 return false;
11427
11428 // If we've fallen outside of the end offset, just pretend there's nothing to
11429 // write to/read from.
11430 if (EndOffset <= LVal.getLValueOffset())
11431 Size = 0;
11432 else
11433 Size = (EndOffset - LVal.getLValueOffset()).getQuantity();
11434 return true;
11435}
11436
11437bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) {
11438 if (unsigned BuiltinOp = E->getBuiltinCallee())
11439 return VisitBuiltinCallExpr(E, BuiltinOp);
11440
11441 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11442}
11443
11444static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info,
11445 APValue &Val, APSInt &Alignment) {
11446 QualType SrcTy = E->getArg(0)->getType();
11447 if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment))
11448 return false;
11449 // Even though we are evaluating integer expressions we could get a pointer
11450 // argument for the __builtin_is_aligned() case.
11451 if (SrcTy->isPointerType()) {
11452 LValue Ptr;
11453 if (!EvaluatePointer(E->getArg(0), Ptr, Info))
11454 return false;
11455 Ptr.moveInto(Val);
11456 } else if (!SrcTy->isIntegralOrEnumerationType()) {
11457 Info.FFDiag(E->getArg(0));
11458 return false;
11459 } else {
11460 APSInt SrcInt;
11461 if (!EvaluateInteger(E->getArg(0), SrcInt, Info))
11462 return false;
11463 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() &&
11464 "Bit widths must be the same");
11465 Val = APValue(SrcInt);
11466 }
11467 assert(Val.hasValue());
11468 return true;
11469}
11470
11471bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
11472 unsigned BuiltinOp) {
11473 switch (BuiltinOp) {
11474 default:
11475 return ExprEvaluatorBaseTy::VisitCallExpr(E);
11476
11477 case Builtin::BI__builtin_dynamic_object_size:
11478 case Builtin::BI__builtin_object_size: {
11479 // The type was checked when we built the expression.
11480 unsigned Type =
11481 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11482 assert(Type <= 3 && "unexpected type");
11483
11484 uint64_t Size;
11485 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size))
11486 return Success(Size, E);
11487
11488 if (E->getArg(0)->HasSideEffects(Info.Ctx))
11489 return Success((Type & 2) ? 0 : -1, E);
11490
11491 // Expression had no side effects, but we couldn't statically determine the
11492 // size of the referenced object.
11493 switch (Info.EvalMode) {
11494 case EvalInfo::EM_ConstantExpression:
11495 case EvalInfo::EM_ConstantFold:
11496 case EvalInfo::EM_IgnoreSideEffects:
11497 // Leave it to IR generation.
11498 return Error(E);
11499 case EvalInfo::EM_ConstantExpressionUnevaluated:
11500 // Reduce it to a constant now.
11501 return Success((Type & 2) ? 0 : -1, E);
11502 }
11503
11504 llvm_unreachable("unexpected EvalMode");
11505 }
11506
11507 case Builtin::BI__builtin_os_log_format_buffer_size: {
11508 analyze_os_log::OSLogBufferLayout Layout;
11509 analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout);
11510 return Success(Layout.size().getQuantity(), E);
11511 }
11512
11513 case Builtin::BI__builtin_is_aligned: {
11514 APValue Src;
11515 APSInt Alignment;
11516 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11517 return false;
11518 if (Src.isLValue()) {
11519 // If we evaluated a pointer, check the minimum known alignment.
11520 LValue Ptr;
11521 Ptr.setFrom(Info.Ctx, Src);
11522 CharUnits BaseAlignment = getBaseAlignment(Info, Ptr);
11523 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset);
11524 // We can return true if the known alignment at the computed offset is
11525 // greater than the requested alignment.
11526 assert(PtrAlign.isPowerOfTwo());
11527 assert(Alignment.isPowerOf2());
11528 if (PtrAlign.getQuantity() >= Alignment)
11529 return Success(1, E);
11530 // If the alignment is not known to be sufficient, some cases could still
11531 // be aligned at run time. However, if the requested alignment is less or
11532 // equal to the base alignment and the offset is not aligned, we know that
11533 // the run-time value can never be aligned.
11534 if (BaseAlignment.getQuantity() >= Alignment &&
11535 PtrAlign.getQuantity() < Alignment)
11536 return Success(0, E);
11537 // Otherwise we can't infer whether the value is sufficiently aligned.
11538 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N)
11539 // in cases where we can't fully evaluate the pointer.
11540 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute)
11541 << Alignment;
11542 return false;
11543 }
11544 assert(Src.isInt());
11545 return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E);
11546 }
11547 case Builtin::BI__builtin_align_up: {
11548 APValue Src;
11549 APSInt Alignment;
11550 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11551 return false;
11552 if (!Src.isInt())
11553 return Error(E);
11554 APSInt AlignedVal =
11555 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1),
11556 Src.getInt().isUnsigned());
11557 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
11558 return Success(AlignedVal, E);
11559 }
11560 case Builtin::BI__builtin_align_down: {
11561 APValue Src;
11562 APSInt Alignment;
11563 if (!getBuiltinAlignArguments(E, Info, Src, Alignment))
11564 return false;
11565 if (!Src.isInt())
11566 return Error(E);
11567 APSInt AlignedVal =
11568 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned());
11569 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth());
11570 return Success(AlignedVal, E);
11571 }
11572
11573 case Builtin::BI__builtin_bitreverse8:
11574 case Builtin::BI__builtin_bitreverse16:
11575 case Builtin::BI__builtin_bitreverse32:
11576 case Builtin::BI__builtin_bitreverse64: {
11577 APSInt Val;
11578 if (!EvaluateInteger(E->getArg(0), Val, Info))
11579 return false;
11580
11581 return Success(Val.reverseBits(), E);
11582 }
11583
11584 case Builtin::BI__builtin_bswap16:
11585 case Builtin::BI__builtin_bswap32:
11586 case Builtin::BI__builtin_bswap64: {
11587 APSInt Val;
11588 if (!EvaluateInteger(E->getArg(0), Val, Info))
11589 return false;
11590
11591 return Success(Val.byteSwap(), E);
11592 }
11593
11594 case Builtin::BI__builtin_classify_type:
11595 return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E);
11596
11597 case Builtin::BI__builtin_clrsb:
11598 case Builtin::BI__builtin_clrsbl:
11599 case Builtin::BI__builtin_clrsbll: {
11600 APSInt Val;
11601 if (!EvaluateInteger(E->getArg(0), Val, Info))
11602 return false;
11603
11604 return Success(Val.getBitWidth() - Val.getMinSignedBits(), E);
11605 }
11606
11607 case Builtin::BI__builtin_clz:
11608 case Builtin::BI__builtin_clzl:
11609 case Builtin::BI__builtin_clzll:
11610 case Builtin::BI__builtin_clzs: {
11611 APSInt Val;
11612 if (!EvaluateInteger(E->getArg(0), Val, Info))
11613 return false;
11614 if (!Val)
11615 return Error(E);
11616
11617 return Success(Val.countLeadingZeros(), E);
11618 }
11619
11620 case Builtin::BI__builtin_constant_p: {
11621 const Expr *Arg = E->getArg(0);
11622 if (EvaluateBuiltinConstantP(Info, Arg))
11623 return Success(true, E);
11624 if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) {
11625 // Outside a constant context, eagerly evaluate to false in the presence
11626 // of side-effects in order to avoid -Wunsequenced false-positives in
11627 // a branch on __builtin_constant_p(expr).
11628 return Success(false, E);
11629 }
11630 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
11631 return false;
11632 }
11633
11634 case Builtin::BI__builtin_is_constant_evaluated: {
11635 const auto *Callee = Info.CurrentCall->getCallee();
11636 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression &&
11637 (Info.CallStackDepth == 1 ||
11638 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() &&
11639 Callee->getIdentifier() &&
11640 Callee->getIdentifier()->isStr("is_constant_evaluated")))) {
11641 // FIXME: Find a better way to avoid duplicated diagnostics.
11642 if (Info.EvalStatus.Diag)
11643 Info.report((Info.CallStackDepth == 1) ? E->getExprLoc()
11644 : Info.CurrentCall->CallLoc,
11645 diag::warn_is_constant_evaluated_always_true_constexpr)
11646 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated"
11647 : "std::is_constant_evaluated");
11648 }
11649
11650 return Success(Info.InConstantContext, E);
11651 }
11652
11653 case Builtin::BI__builtin_ctz:
11654 case Builtin::BI__builtin_ctzl:
11655 case Builtin::BI__builtin_ctzll:
11656 case Builtin::BI__builtin_ctzs: {
11657 APSInt Val;
11658 if (!EvaluateInteger(E->getArg(0), Val, Info))
11659 return false;
11660 if (!Val)
11661 return Error(E);
11662
11663 return Success(Val.countTrailingZeros(), E);
11664 }
11665
11666 case Builtin::BI__builtin_eh_return_data_regno: {
11667 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue();
11668 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand);
11669 return Success(Operand, E);
11670 }
11671
11672 case Builtin::BI__builtin_expect:
11673 case Builtin::BI__builtin_expect_with_probability:
11674 return Visit(E->getArg(0));
11675
11676 case Builtin::BI__builtin_ffs:
11677 case Builtin::BI__builtin_ffsl:
11678 case Builtin::BI__builtin_ffsll: {
11679 APSInt Val;
11680 if (!EvaluateInteger(E->getArg(0), Val, Info))
11681 return false;
11682
11683 unsigned N = Val.countTrailingZeros();
11684 return Success(N == Val.getBitWidth() ? 0 : N + 1, E);
11685 }
11686
11687 case Builtin::BI__builtin_fpclassify: {
11688 APFloat Val(0.0);
11689 if (!EvaluateFloat(E->getArg(5), Val, Info))
11690 return false;
11691 unsigned Arg;
11692 switch (Val.getCategory()) {
11693 case APFloat::fcNaN: Arg = 0; break;
11694 case APFloat::fcInfinity: Arg = 1; break;
11695 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break;
11696 case APFloat::fcZero: Arg = 4; break;
11697 }
11698 return Visit(E->getArg(Arg));
11699 }
11700
11701 case Builtin::BI__builtin_isinf_sign: {
11702 APFloat Val(0.0);
11703 return EvaluateFloat(E->getArg(0), Val, Info) &&
11704 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E);
11705 }
11706
11707 case Builtin::BI__builtin_isinf: {
11708 APFloat Val(0.0);
11709 return EvaluateFloat(E->getArg(0), Val, Info) &&
11710 Success(Val.isInfinity() ? 1 : 0, E);
11711 }
11712
11713 case Builtin::BI__builtin_isfinite: {
11714 APFloat Val(0.0);
11715 return EvaluateFloat(E->getArg(0), Val, Info) &&
11716 Success(Val.isFinite() ? 1 : 0, E);
11717 }
11718
11719 case Builtin::BI__builtin_isnan: {
11720 APFloat Val(0.0);
11721 return EvaluateFloat(E->getArg(0), Val, Info) &&
11722 Success(Val.isNaN() ? 1 : 0, E);
11723 }
11724
11725 case Builtin::BI__builtin_isnormal: {
11726 APFloat Val(0.0);
11727 return EvaluateFloat(E->getArg(0), Val, Info) &&
11728 Success(Val.isNormal() ? 1 : 0, E);
11729 }
11730
11731 case Builtin::BI__builtin_parity:
11732 case Builtin::BI__builtin_parityl:
11733 case Builtin::BI__builtin_parityll: {
11734 APSInt Val;
11735 if (!EvaluateInteger(E->getArg(0), Val, Info))
11736 return false;
11737
11738 return Success(Val.countPopulation() % 2, E);
11739 }
11740
11741 case Builtin::BI__builtin_popcount:
11742 case Builtin::BI__builtin_popcountl:
11743 case Builtin::BI__builtin_popcountll: {
11744 APSInt Val;
11745 if (!EvaluateInteger(E->getArg(0), Val, Info))
11746 return false;
11747
11748 return Success(Val.countPopulation(), E);
11749 }
11750
11751 case Builtin::BI__builtin_rotateleft8:
11752 case Builtin::BI__builtin_rotateleft16:
11753 case Builtin::BI__builtin_rotateleft32:
11754 case Builtin::BI__builtin_rotateleft64:
11755 case Builtin::BI_rotl8: // Microsoft variants of rotate right
11756 case Builtin::BI_rotl16:
11757 case Builtin::BI_rotl:
11758 case Builtin::BI_lrotl:
11759 case Builtin::BI_rotl64: {
11760 APSInt Val, Amt;
11761 if (!EvaluateInteger(E->getArg(0), Val, Info) ||
11762 !EvaluateInteger(E->getArg(1), Amt, Info))
11763 return false;
11764
11765 return Success(Val.rotl(Amt.urem(Val.getBitWidth())), E);
11766 }
11767
11768 case Builtin::BI__builtin_rotateright8:
11769 case Builtin::BI__builtin_rotateright16:
11770 case Builtin::BI__builtin_rotateright32:
11771 case Builtin::BI__builtin_rotateright64:
11772 case Builtin::BI_rotr8: // Microsoft variants of rotate right
11773 case Builtin::BI_rotr16:
11774 case Builtin::BI_rotr:
11775 case Builtin::BI_lrotr:
11776 case Builtin::BI_rotr64: {
11777 APSInt Val, Amt;
11778 if (!EvaluateInteger(E->getArg(0), Val, Info) ||
11779 !EvaluateInteger(E->getArg(1), Amt, Info))
11780 return false;
11781
11782 return Success(Val.rotr(Amt.urem(Val.getBitWidth())), E);
11783 }
11784
11785 case Builtin::BIstrlen:
11786 case Builtin::BIwcslen:
11787 // A call to strlen is not a constant expression.
11788 if (Info.getLangOpts().CPlusPlus11)
11789 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11790 << /*isConstexpr*/0 << /*isConstructor*/0
11791 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11792 else
11793 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11794 LLVM_FALLTHROUGH;
11795 case Builtin::BI__builtin_strlen:
11796 case Builtin::BI__builtin_wcslen: {
11797 // As an extension, we support __builtin_strlen() as a constant expression,
11798 // and support folding strlen() to a constant.
11799 LValue String;
11800 if (!EvaluatePointer(E->getArg(0), String, Info))
11801 return false;
11802
11803 QualType CharTy = E->getArg(0)->getType()->getPointeeType();
11804
11805 // Fast path: if it's a string literal, search the string value.
11806 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>(
11807 String.getLValueBase().dyn_cast<const Expr *>())) {
11808 // The string literal may have embedded null characters. Find the first
11809 // one and truncate there.
11810 StringRef Str = S->getBytes();
11811 int64_t Off = String.Offset.getQuantity();
11812 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() &&
11813 S->getCharByteWidth() == 1 &&
11814 // FIXME: Add fast-path for wchar_t too.
11815 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) {
11816 Str = Str.substr(Off);
11817
11818 StringRef::size_type Pos = Str.find(0);
11819 if (Pos != StringRef::npos)
11820 Str = Str.substr(0, Pos);
11821
11822 return Success(Str.size(), E);
11823 }
11824
11825 // Fall through to slow path to issue appropriate diagnostic.
11826 }
11827
11828 // Slow path: scan the bytes of the string looking for the terminating 0.
11829 for (uint64_t Strlen = 0; /**/; ++Strlen) {
11830 APValue Char;
11831 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) ||
11832 !Char.isInt())
11833 return false;
11834 if (!Char.getInt())
11835 return Success(Strlen, E);
11836 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1))
11837 return false;
11838 }
11839 }
11840
11841 case Builtin::BIstrcmp:
11842 case Builtin::BIwcscmp:
11843 case Builtin::BIstrncmp:
11844 case Builtin::BIwcsncmp:
11845 case Builtin::BImemcmp:
11846 case Builtin::BIbcmp:
11847 case Builtin::BIwmemcmp:
11848 // A call to strlen is not a constant expression.
11849 if (Info.getLangOpts().CPlusPlus11)
11850 Info.CCEDiag(E, diag::note_constexpr_invalid_function)
11851 << /*isConstexpr*/0 << /*isConstructor*/0
11852 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'");
11853 else
11854 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr);
11855 LLVM_FALLTHROUGH;
11856 case Builtin::BI__builtin_strcmp:
11857 case Builtin::BI__builtin_wcscmp:
11858 case Builtin::BI__builtin_strncmp:
11859 case Builtin::BI__builtin_wcsncmp:
11860 case Builtin::BI__builtin_memcmp:
11861 case Builtin::BI__builtin_bcmp:
11862 case Builtin::BI__builtin_wmemcmp: {
11863 LValue String1, String2;
11864 if (!EvaluatePointer(E->getArg(0), String1, Info) ||
11865 !EvaluatePointer(E->getArg(1), String2, Info))
11866 return false;
11867
11868 uint64_t MaxLength = uint64_t(-1);
11869 if (BuiltinOp != Builtin::BIstrcmp &&
11870 BuiltinOp != Builtin::BIwcscmp &&
11871 BuiltinOp != Builtin::BI__builtin_strcmp &&
11872 BuiltinOp != Builtin::BI__builtin_wcscmp) {
11873 APSInt N;
11874 if (!EvaluateInteger(E->getArg(2), N, Info))
11875 return false;
11876 MaxLength = N.getExtValue();
11877 }
11878
11879 // Empty substrings compare equal by definition.
11880 if (MaxLength == 0u)
11881 return Success(0, E);
11882
11883 if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11884 !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) ||
11885 String1.Designator.Invalid || String2.Designator.Invalid)
11886 return false;
11887
11888 QualType CharTy1 = String1.Designator.getType(Info.Ctx);
11889 QualType CharTy2 = String2.Designator.getType(Info.Ctx);
11890
11891 bool IsRawByte = BuiltinOp == Builtin::BImemcmp ||
11892 BuiltinOp == Builtin::BIbcmp ||
11893 BuiltinOp == Builtin::BI__builtin_memcmp ||
11894 BuiltinOp == Builtin::BI__builtin_bcmp;
11895
11896 assert(IsRawByte ||
11897 (Info.Ctx.hasSameUnqualifiedType(
11898 CharTy1, E->getArg(0)->getType()->getPointeeType()) &&
11899 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2)));
11900
11901 // For memcmp, allow comparing any arrays of '[[un]signed] char' or
11902 // 'char8_t', but no other types.
11903 if (IsRawByte &&
11904 !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) {
11905 // FIXME: Consider using our bit_cast implementation to support this.
11906 Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported)
11907 << (std::string("'") + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'")
11908 << CharTy1 << CharTy2;
11909 return false;
11910 }
11911
11912 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) {
11913 return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) &&
11914 handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) &&
11915 Char1.isInt() && Char2.isInt();
11916 };
11917 const auto &AdvanceElems = [&] {
11918 return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) &&
11919 HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1);
11920 };
11921
11922 bool StopAtNull =
11923 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp &&
11924 BuiltinOp != Builtin::BIwmemcmp &&
11925 BuiltinOp != Builtin::BI__builtin_memcmp &&
11926 BuiltinOp != Builtin::BI__builtin_bcmp &&
11927 BuiltinOp != Builtin::BI__builtin_wmemcmp);
11928 bool IsWide = BuiltinOp == Builtin::BIwcscmp ||
11929 BuiltinOp == Builtin::BIwcsncmp ||
11930 BuiltinOp == Builtin::BIwmemcmp ||
11931 BuiltinOp == Builtin::BI__builtin_wcscmp ||
11932 BuiltinOp == Builtin::BI__builtin_wcsncmp ||
11933 BuiltinOp == Builtin::BI__builtin_wmemcmp;
11934
11935 for (; MaxLength; --MaxLength) {
11936 APValue Char1, Char2;
11937 if (!ReadCurElems(Char1, Char2))
11938 return false;
11939 if (Char1.getInt().ne(Char2.getInt())) {
11940 if (IsWide) // wmemcmp compares with wchar_t signedness.
11941 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E);
11942 // memcmp always compares unsigned chars.
11943 return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E);
11944 }
11945 if (StopAtNull && !Char1.getInt())
11946 return Success(0, E);
11947 assert(!(StopAtNull && !Char2.getInt()));
11948 if (!AdvanceElems())
11949 return false;
11950 }
11951 // We hit the strncmp / memcmp limit.
11952 return Success(0, E);
11953 }
11954
11955 case Builtin::BI__atomic_always_lock_free:
11956 case Builtin::BI__atomic_is_lock_free:
11957 case Builtin::BI__c11_atomic_is_lock_free: {
11958 APSInt SizeVal;
11959 if (!EvaluateInteger(E->getArg(0), SizeVal, Info))
11960 return false;
11961
11962 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power
11963 // of two less than or equal to the maximum inline atomic width, we know it
11964 // is lock-free. If the size isn't a power of two, or greater than the
11965 // maximum alignment where we promote atomics, we know it is not lock-free
11966 // (at least not in the sense of atomic_is_lock_free). Otherwise,
11967 // the answer can only be determined at runtime; for example, 16-byte
11968 // atomics have lock-free implementations on some, but not all,
11969 // x86-64 processors.
11970
11971 // Check power-of-two.
11972 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue());
11973 if (Size.isPowerOfTwo()) {
11974 // Check against inlining width.
11975 unsigned InlineWidthBits =
11976 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth();
11977 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) {
11978 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free ||
11979 Size == CharUnits::One() ||
11980 E->getArg(1)->isNullPointerConstant(Info.Ctx,
11981 Expr::NPC_NeverValueDependent))
11982 // OK, we will inline appropriately-aligned operations of this size,
11983 // and _Atomic(T) is appropriately-aligned.
11984 return Success(1, E);
11985
11986 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()->
11987 castAs<PointerType>()->getPointeeType();
11988 if (!PointeeType->isIncompleteType() &&
11989 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) {
11990 // OK, we will inline operations on this object.
11991 return Success(1, E);
11992 }
11993 }
11994 }
11995
11996 return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
11997 Success(0, E) : Error(E);
11998 }
11999 case Builtin::BIomp_is_initial_device:
12000 // We can decide statically which value the runtime would return if called.
12001 return Success(Info.getLangOpts().OpenMPIsDevice ? 0 : 1, E);
12002 case Builtin::BI__builtin_add_overflow:
12003 case Builtin::BI__builtin_sub_overflow:
12004 case Builtin::BI__builtin_mul_overflow:
12005 case Builtin::BI__builtin_sadd_overflow:
12006 case Builtin::BI__builtin_uadd_overflow:
12007 case Builtin::BI__builtin_uaddl_overflow:
12008 case Builtin::BI__builtin_uaddll_overflow:
12009 case Builtin::BI__builtin_usub_overflow:
12010 case Builtin::BI__builtin_usubl_overflow:
12011 case Builtin::BI__builtin_usubll_overflow:
12012 case Builtin::BI__builtin_umul_overflow:
12013 case Builtin::BI__builtin_umull_overflow:
12014 case Builtin::BI__builtin_umulll_overflow:
12015 case Builtin::BI__builtin_saddl_overflow:
12016 case Builtin::BI__builtin_saddll_overflow:
12017 case Builtin::BI__builtin_ssub_overflow:
12018 case Builtin::BI__builtin_ssubl_overflow:
12019 case Builtin::BI__builtin_ssubll_overflow:
12020 case Builtin::BI__builtin_smul_overflow:
12021 case Builtin::BI__builtin_smull_overflow:
12022 case Builtin::BI__builtin_smulll_overflow: {
12023 LValue ResultLValue;
12024 APSInt LHS, RHS;
12025
12026 QualType ResultType = E->getArg(2)->getType()->getPointeeType();
12027 if (!EvaluateInteger(E->getArg(0), LHS, Info) ||
12028 !EvaluateInteger(E->getArg(1), RHS, Info) ||
12029 !EvaluatePointer(E->getArg(2), ResultLValue, Info))
12030 return false;
12031
12032 APSInt Result;
12033 bool DidOverflow = false;
12034
12035 // If the types don't have to match, enlarge all 3 to the largest of them.
12036 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12037 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12038 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12039 bool IsSigned = LHS.isSigned() || RHS.isSigned() ||
12040 ResultType->isSignedIntegerOrEnumerationType();
12041 bool AllSigned = LHS.isSigned() && RHS.isSigned() &&
12042 ResultType->isSignedIntegerOrEnumerationType();
12043 uint64_t LHSSize = LHS.getBitWidth();
12044 uint64_t RHSSize = RHS.getBitWidth();
12045 uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType);
12046 uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize);
12047
12048 // Add an additional bit if the signedness isn't uniformly agreed to. We
12049 // could do this ONLY if there is a signed and an unsigned that both have
12050 // MaxBits, but the code to check that is pretty nasty. The issue will be
12051 // caught in the shrink-to-result later anyway.
12052 if (IsSigned && !AllSigned)
12053 ++MaxBits;
12054
12055 LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned);
12056 RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned);
12057 Result = APSInt(MaxBits, !IsSigned);
12058 }
12059
12060 // Find largest int.
12061 switch (BuiltinOp) {
12062 default:
12063 llvm_unreachable("Invalid value for BuiltinOp");
12064 case Builtin::BI__builtin_add_overflow:
12065 case Builtin::BI__builtin_sadd_overflow:
12066 case Builtin::BI__builtin_saddl_overflow:
12067 case Builtin::BI__builtin_saddll_overflow:
12068 case Builtin::BI__builtin_uadd_overflow:
12069 case Builtin::BI__builtin_uaddl_overflow:
12070 case Builtin::BI__builtin_uaddll_overflow:
12071 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow)
12072 : LHS.uadd_ov(RHS, DidOverflow);
12073 break;
12074 case Builtin::BI__builtin_sub_overflow:
12075 case Builtin::BI__builtin_ssub_overflow:
12076 case Builtin::BI__builtin_ssubl_overflow:
12077 case Builtin::BI__builtin_ssubll_overflow:
12078 case Builtin::BI__builtin_usub_overflow:
12079 case Builtin::BI__builtin_usubl_overflow:
12080 case Builtin::BI__builtin_usubll_overflow:
12081 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow)
12082 : LHS.usub_ov(RHS, DidOverflow);
12083 break;
12084 case Builtin::BI__builtin_mul_overflow:
12085 case Builtin::BI__builtin_smul_overflow:
12086 case Builtin::BI__builtin_smull_overflow:
12087 case Builtin::BI__builtin_smulll_overflow:
12088 case Builtin::BI__builtin_umul_overflow:
12089 case Builtin::BI__builtin_umull_overflow:
12090 case Builtin::BI__builtin_umulll_overflow:
12091 Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow)
12092 : LHS.umul_ov(RHS, DidOverflow);
12093 break;
12094 }
12095
12096 // In the case where multiple sizes are allowed, truncate and see if
12097 // the values are the same.
12098 if (BuiltinOp == Builtin::BI__builtin_add_overflow ||
12099 BuiltinOp == Builtin::BI__builtin_sub_overflow ||
12100 BuiltinOp == Builtin::BI__builtin_mul_overflow) {
12101 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead,
12102 // since it will give us the behavior of a TruncOrSelf in the case where
12103 // its parameter <= its size. We previously set Result to be at least the
12104 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth
12105 // will work exactly like TruncOrSelf.
12106 APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType));
12107 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType());
12108
12109 if (!APSInt::isSameValue(Temp, Result))
12110 DidOverflow = true;
12111 Result = Temp;
12112 }
12113
12114 APValue APV{Result};
12115 if (!handleAssignment(Info, E, ResultLValue, ResultType, APV))
12116 return false;
12117 return Success(DidOverflow, E);
12118 }
12119 }
12120}
12121
12122/// Determine whether this is a pointer past the end of the complete
12123/// object referred to by the lvalue.
12124static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
12125 const LValue &LV) {
12126 // A null pointer can be viewed as being "past the end" but we don't
12127 // choose to look at it that way here.
12128 if (!LV.getLValueBase())
12129 return false;
12130
12131 // If the designator is valid and refers to a subobject, we're not pointing
12132 // past the end.
12133 if (!LV.getLValueDesignator().Invalid &&
12134 !LV.getLValueDesignator().isOnePastTheEnd())
12135 return false;
12136
12137 // A pointer to an incomplete type might be past-the-end if the type's size is
12138 // zero. We cannot tell because the type is incomplete.
12139 QualType Ty = getType(LV.getLValueBase());
12140 if (Ty->isIncompleteType())
12141 return true;
12142
12143 // We're a past-the-end pointer if we point to the byte after the object,
12144 // no matter what our type or path is.
12145 auto Size = Ctx.getTypeSizeInChars(Ty);
12146 return LV.getLValueOffset() == Size;
12147}
12148
12149namespace {
12150
12151/// Data recursive integer evaluator of certain binary operators.
12152///
12153/// We use a data recursive algorithm for binary operators so that we are able
12154/// to handle extreme cases of chained binary operators without causing stack
12155/// overflow.
12156class DataRecursiveIntBinOpEvaluator {
12157 struct EvalResult {
12158 APValue Val;
12159 bool Failed;
12160
12161 EvalResult() : Failed(false) { }
12162
12163 void swap(EvalResult &RHS) {
12164 Val.swap(RHS.Val);
12165 Failed = RHS.Failed;
12166 RHS.Failed = false;
12167 }
12168 };
12169
12170 struct Job {
12171 const Expr *E;
12172 EvalResult LHSResult; // meaningful only for binary operator expression.
12173 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind;
12174
12175 Job() = default;
12176 Job(Job &&) = default;
12177
12178 void startSpeculativeEval(EvalInfo &Info) {
12179 SpecEvalRAII = SpeculativeEvaluationRAII(Info);
12180 }
12181
12182 private:
12183 SpeculativeEvaluationRAII SpecEvalRAII;
12184 };
12185
12186 SmallVector<Job, 16> Queue;
12187
12188 IntExprEvaluator &IntEval;
12189 EvalInfo &Info;
12190 APValue &FinalResult;
12191
12192public:
12193 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result)
12194 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { }
12195
12196 /// True if \param E is a binary operator that we are going to handle
12197 /// data recursively.
12198 /// We handle binary operators that are comma, logical, or that have operands
12199 /// with integral or enumeration type.
12200 static bool shouldEnqueue(const BinaryOperator *E) {
12201 return E->getOpcode() == BO_Comma || E->isLogicalOp() ||
12202 (E->isRValue() && E->getType()->isIntegralOrEnumerationType() &&
12203 E->getLHS()->getType()->isIntegralOrEnumerationType() &&
12204 E->getRHS()->getType()->isIntegralOrEnumerationType());
12205 }
12206
12207 bool Traverse(const BinaryOperator *E) {
12208 enqueue(E);
12209 EvalResult PrevResult;
12210 while (!Queue.empty())
12211 process(PrevResult);
12212
12213 if (PrevResult.Failed) return false;
12214
12215 FinalResult.swap(PrevResult.Val);
12216 return true;
12217 }
12218
12219private:
12220 bool Success(uint64_t Value, const Expr *E, APValue &Result) {
12221 return IntEval.Success(Value, E, Result);
12222 }
12223 bool Success(const APSInt &Value, const Expr *E, APValue &Result) {
12224 return IntEval.Success(Value, E, Result);
12225 }
12226 bool Error(const Expr *E) {
12227 return IntEval.Error(E);
12228 }
12229 bool Error(const Expr *E, diag::kind D) {
12230 return IntEval.Error(E, D);
12231 }
12232
12233 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) {
12234 return Info.CCEDiag(E, D);
12235 }
12236
12237 // Returns true if visiting the RHS is necessary, false otherwise.
12238 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
12239 bool &SuppressRHSDiags);
12240
12241 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
12242 const BinaryOperator *E, APValue &Result);
12243
12244 void EvaluateExpr(const Expr *E, EvalResult &Result) {
12245 Result.Failed = !Evaluate(Result.Val, Info, E);
12246 if (Result.Failed)
12247 Result.Val = APValue();
12248 }
12249
12250 void process(EvalResult &Result);
12251
12252 void enqueue(const Expr *E) {
12253 E = E->IgnoreParens();
12254 Queue.resize(Queue.size()+1);
12255 Queue.back().E = E;
12256 Queue.back().Kind = Job::AnyExprKind;
12257 }
12258};
12259
12260}
12261
12262bool DataRecursiveIntBinOpEvaluator::
12263 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E,
12264 bool &SuppressRHSDiags) {
12265 if (E->getOpcode() == BO_Comma) {
12266 // Ignore LHS but note if we could not evaluate it.
12267 if (LHSResult.Failed)
12268 return Info.noteSideEffect();
12269 return true;
12270 }
12271
12272 if (E->isLogicalOp()) {
12273 bool LHSAsBool;
12274 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) {
12275 // We were able to evaluate the LHS, see if we can get away with not
12276 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
12277 if (LHSAsBool == (E->getOpcode() == BO_LOr)) {
12278 Success(LHSAsBool, E, LHSResult.Val);
12279 return false; // Ignore RHS
12280 }
12281 } else {
12282 LHSResult.Failed = true;
12283
12284 // Since we weren't able to evaluate the left hand side, it
12285 // might have had side effects.
12286 if (!Info.noteSideEffect())
12287 return false;
12288
12289 // We can't evaluate the LHS; however, sometimes the result
12290 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
12291 // Don't ignore RHS and suppress diagnostics from this arm.
12292 SuppressRHSDiags = true;
12293 }
12294
12295 return true;
12296 }
12297
12298 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
12299 E->getRHS()->getType()->isIntegralOrEnumerationType());
12300
12301 if (LHSResult.Failed && !Info.noteFailure())
12302 return false; // Ignore RHS;
12303
12304 return true;
12305}
12306
12307static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index,
12308 bool IsSub) {
12309 // Compute the new offset in the appropriate width, wrapping at 64 bits.
12310 // FIXME: When compiling for a 32-bit target, we should use 32-bit
12311 // offsets.
12312 assert(!LVal.hasLValuePath() && "have designator for integer lvalue");
12313 CharUnits &Offset = LVal.getLValueOffset();
12314 uint64_t Offset64 = Offset.getQuantity();
12315 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue();
12316 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64
12317 : Offset64 + Index64);
12318}
12319
12320bool DataRecursiveIntBinOpEvaluator::
12321 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult,
12322 const BinaryOperator *E, APValue &Result) {
12323 if (E->getOpcode() == BO_Comma) {
12324 if (RHSResult.Failed)
12325 return false;
12326 Result = RHSResult.Val;
12327 return true;
12328 }
12329
12330 if (E->isLogicalOp()) {
12331 bool lhsResult, rhsResult;
12332 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
12333 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
12334
12335 if (LHSIsOK) {
12336 if (RHSIsOK) {
12337 if (E->getOpcode() == BO_LOr)
12338 return Success(lhsResult || rhsResult, E, Result);
12339 else
12340 return Success(lhsResult && rhsResult, E, Result);
12341 }
12342 } else {
12343 if (RHSIsOK) {
12344 // We can't evaluate the LHS; however, sometimes the result
12345 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
12346 if (rhsResult == (E->getOpcode() == BO_LOr))
12347 return Success(rhsResult, E, Result);
12348 }
12349 }
12350
12351 return false;
12352 }
12353
12354 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
12355 E->getRHS()->getType()->isIntegralOrEnumerationType());
12356
12357 if (LHSResult.Failed || RHSResult.Failed)
12358 return false;
12359
12360 const APValue &LHSVal = LHSResult.Val;
12361 const APValue &RHSVal = RHSResult.Val;
12362
12363 // Handle cases like (unsigned long)&a + 4.
12364 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
12365 Result = LHSVal;
12366 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
12367 return true;
12368 }
12369
12370 // Handle cases like 4 + (unsigned long)&a
12371 if (E->getOpcode() == BO_Add &&
12372 RHSVal.isLValue() && LHSVal.isInt()) {
12373 Result = RHSVal;
12374 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
12375 return true;
12376 }
12377
12378 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
12379 // Handle (intptr_t)&&A - (intptr_t)&&B.
12380 if (!LHSVal.getLValueOffset().isZero() ||
12381 !RHSVal.getLValueOffset().isZero())
12382 return false;
12383 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>();
12384 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>();
12385 if (!LHSExpr || !RHSExpr)
12386 return false;
12387 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
12388 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
12389 if (!LHSAddrExpr || !RHSAddrExpr)
12390 return false;
12391 // Make sure both labels come from the same function.
12392 if (LHSAddrExpr->getLabel()->getDeclContext() !=
12393 RHSAddrExpr->getLabel()->getDeclContext())
12394 return false;
12395 Result = APValue(LHSAddrExpr, RHSAddrExpr);
12396 return true;
12397 }
12398
12399 // All the remaining cases expect both operands to be an integer
12400 if (!LHSVal.isInt() || !RHSVal.isInt())
12401 return Error(E);
12402
12403 // Set up the width and signedness manually, in case it can't be deduced
12404 // from the operation we're performing.
12405 // FIXME: Don't do this in the cases where we can deduce it.
12406 APSInt Value(Info.Ctx.getIntWidth(E->getType()),
12407 E->getType()->isUnsignedIntegerOrEnumerationType());
12408 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(),
12409 RHSVal.getInt(), Value))
12410 return false;
12411 return Success(Value, E, Result);
12412}
12413
12414void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
12415 Job &job = Queue.back();
12416
12417 switch (job.Kind) {
12418 case Job::AnyExprKind: {
12419 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
12420 if (shouldEnqueue(Bop)) {
12421 job.Kind = Job::BinOpKind;
12422 enqueue(Bop->getLHS());
12423 return;
12424 }
12425 }
12426
12427 EvaluateExpr(job.E, Result);
12428 Queue.pop_back();
12429 return;
12430 }
12431
12432 case Job::BinOpKind: {
12433 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
12434 bool SuppressRHSDiags = false;
12435 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) {
12436 Queue.pop_back();
12437 return;
12438 }
12439 if (SuppressRHSDiags)
12440 job.startSpeculativeEval(Info);
12441 job.LHSResult.swap(Result);
12442 job.Kind = Job::BinOpVisitedLHSKind;
12443 enqueue(Bop->getRHS());
12444 return;
12445 }
12446
12447 case Job::BinOpVisitedLHSKind: {
12448 const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
12449 EvalResult RHS;
12450 RHS.swap(Result);
12451 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val);
12452 Queue.pop_back();
12453 return;
12454 }
12455 }
12456
12457 llvm_unreachable("Invalid Job::Kind!");
12458}
12459
12460namespace {
12461/// Used when we determine that we should fail, but can keep evaluating prior to
12462/// noting that we had a failure.
12463class DelayedNoteFailureRAII {
12464 EvalInfo &Info;
12465 bool NoteFailure;
12466
12467public:
12468 DelayedNoteFailureRAII(EvalInfo &Info, bool NoteFailure = true)
12469 : Info(Info), NoteFailure(NoteFailure) {}
12470 ~DelayedNoteFailureRAII() {
12471 if (NoteFailure) {
12472 bool ContinueAfterFailure = Info.noteFailure();
12473 (void)ContinueAfterFailure;
12474 assert(ContinueAfterFailure &&
12475 "Shouldn't have kept evaluating on failure.");
12476 }
12477 }
12478};
12479
12480enum class CmpResult {
12481 Unequal,
12482 Less,
12483 Equal,
12484 Greater,
12485 Unordered,
12486};
12487}
12488
12489template <class SuccessCB, class AfterCB>
12490static bool
12491EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E,
12492 SuccessCB &&Success, AfterCB &&DoAfter) {
12493 assert(!E->isValueDependent());
12494 assert(E->isComparisonOp() && "expected comparison operator");
12495 assert((E->getOpcode() == BO_Cmp ||
12496 E->getType()->isIntegralOrEnumerationType()) &&
12497 "unsupported binary expression evaluation");
12498 auto Error = [&](const Expr *E) {
12499 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
12500 return false;
12501 };
12502
12503 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp;
12504 bool IsEquality = E->isEqualityOp();
12505
12506 QualType LHSTy = E->getLHS()->getType();
12507 QualType RHSTy = E->getRHS()->getType();
12508
12509 if (LHSTy->isIntegralOrEnumerationType() &&
12510 RHSTy->isIntegralOrEnumerationType()) {
12511 APSInt LHS, RHS;
12512 bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info);
12513 if (!LHSOK && !Info.noteFailure())
12514 return false;
12515 if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK)
12516 return false;
12517 if (LHS < RHS)
12518 return Success(CmpResult::Less, E);
12519 if (LHS > RHS)
12520 return Success(CmpResult::Greater, E);
12521 return Success(CmpResult::Equal, E);
12522 }
12523
12524 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) {
12525 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy));
12526 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy));
12527
12528 bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info);
12529 if (!LHSOK && !Info.noteFailure())
12530 return false;
12531 if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK)
12532 return false;
12533 if (LHSFX < RHSFX)
12534 return Success(CmpResult::Less, E);
12535 if (LHSFX > RHSFX)
12536 return Success(CmpResult::Greater, E);
12537 return Success(CmpResult::Equal, E);
12538 }
12539
12540 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) {
12541 ComplexValue LHS, RHS;
12542 bool LHSOK;
12543 if (E->isAssignmentOp()) {
12544 LValue LV;
12545 EvaluateLValue(E->getLHS(), LV, Info);
12546 LHSOK = false;
12547 } else if (LHSTy->isRealFloatingType()) {
12548 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info);
12549 if (LHSOK) {
12550 LHS.makeComplexFloat();
12551 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics());
12552 }
12553 } else {
12554 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info);
12555 }
12556 if (!LHSOK && !Info.noteFailure())
12557 return false;
12558
12559 if (E->getRHS()->getType()->isRealFloatingType()) {
12560 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK)
12561 return false;
12562 RHS.makeComplexFloat();
12563 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics());
12564 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
12565 return false;
12566
12567 if (LHS.isComplexFloat()) {
12568 APFloat::cmpResult CR_r =
12569 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal());
12570 APFloat::cmpResult CR_i =
12571 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag());
12572 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual;
12573 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12574 } else {
12575 assert(IsEquality && "invalid complex comparison");
12576 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() &&
12577 LHS.getComplexIntImag() == RHS.getComplexIntImag();
12578 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E);
12579 }
12580 }
12581
12582 if (LHSTy->isRealFloatingType() &&
12583 RHSTy->isRealFloatingType()) {
12584 APFloat RHS(0.0), LHS(0.0);
12585
12586 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info);
12587 if (!LHSOK && !Info.noteFailure())
12588 return false;
12589
12590 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK)
12591 return false;
12592
12593 assert(E->isComparisonOp() && "Invalid binary operator!");
12594 llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS);
12595 if (!Info.InConstantContext &&
12596 APFloatCmpResult == APFloat::cmpUnordered &&
12597 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).isFPConstrained()) {
12598 // Note: Compares may raise invalid in some cases involving NaN or sNaN.
12599 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict);
12600 return false;
12601 }
12602 auto GetCmpRes = [&]() {
12603 switch (APFloatCmpResult) {
12604 case APFloat::cmpEqual:
12605 return CmpResult::Equal;
12606 case APFloat::cmpLessThan:
12607 return CmpResult::Less;
12608 case APFloat::cmpGreaterThan:
12609 return CmpResult::Greater;
12610 case APFloat::cmpUnordered:
12611 return CmpResult::Unordered;
12612 }
12613 llvm_unreachable("Unrecognised APFloat::cmpResult enum");
12614 };
12615 return Success(GetCmpRes(), E);
12616 }
12617
12618 if (LHSTy->isPointerType() && RHSTy->isPointerType()) {
12619 LValue LHSValue, RHSValue;
12620
12621 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12622 if (!LHSOK && !Info.noteFailure())
12623 return false;
12624
12625 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12626 return false;
12627
12628 // Reject differing bases from the normal codepath; we special-case
12629 // comparisons to null.
12630 if (!HasSameBase(LHSValue, RHSValue)) {
12631 // Inequalities and subtractions between unrelated pointers have
12632 // unspecified or undefined behavior.
12633 if (!IsEquality) {
12634 Info.FFDiag(E, diag::note_constexpr_pointer_comparison_unspecified);
12635 return false;
12636 }
12637 // A constant address may compare equal to the address of a symbol.
12638 // The one exception is that address of an object cannot compare equal
12639 // to a null pointer constant.
12640 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) ||
12641 (!RHSValue.Base && !RHSValue.Offset.isZero()))
12642 return Error(E);
12643 // It's implementation-defined whether distinct literals will have
12644 // distinct addresses. In clang, the result of such a comparison is
12645 // unspecified, so it is not a constant expression. However, we do know
12646 // that the address of a literal will be non-null.
12647 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) &&
12648 LHSValue.Base && RHSValue.Base)
12649 return Error(E);
12650 // We can't tell whether weak symbols will end up pointing to the same
12651 // object.
12652 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue))
12653 return Error(E);
12654 // We can't compare the address of the start of one object with the
12655 // past-the-end address of another object, per C++ DR1652.
12656 if ((LHSValue.Base && LHSValue.Offset.isZero() &&
12657 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) ||
12658 (RHSValue.Base && RHSValue.Offset.isZero() &&
12659 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)))
12660 return Error(E);
12661 // We can't tell whether an object is at the same address as another
12662 // zero sized object.
12663 if ((RHSValue.Base && isZeroSized(LHSValue)) ||
12664 (LHSValue.Base && isZeroSized(RHSValue)))
12665 return Error(E);
12666 return Success(CmpResult::Unequal, E);
12667 }
12668
12669 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12670 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12671
12672 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12673 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12674
12675 // C++11 [expr.rel]p3:
12676 // Pointers to void (after pointer conversions) can be compared, with a
12677 // result defined as follows: If both pointers represent the same
12678 // address or are both the null pointer value, the result is true if the
12679 // operator is <= or >= and false otherwise; otherwise the result is
12680 // unspecified.
12681 // We interpret this as applying to pointers to *cv* void.
12682 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational)
12683 Info.CCEDiag(E, diag::note_constexpr_void_comparison);
12684
12685 // C++11 [expr.rel]p2:
12686 // - If two pointers point to non-static data members of the same object,
12687 // or to subobjects or array elements fo such members, recursively, the
12688 // pointer to the later declared member compares greater provided the
12689 // two members have the same access control and provided their class is
12690 // not a union.
12691 // [...]
12692 // - Otherwise pointer comparisons are unspecified.
12693 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) {
12694 bool WasArrayIndex;
12695 unsigned Mismatch = FindDesignatorMismatch(
12696 getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex);
12697 // At the point where the designators diverge, the comparison has a
12698 // specified value if:
12699 // - we are comparing array indices
12700 // - we are comparing fields of a union, or fields with the same access
12701 // Otherwise, the result is unspecified and thus the comparison is not a
12702 // constant expression.
12703 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() &&
12704 Mismatch < RHSDesignator.Entries.size()) {
12705 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]);
12706 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]);
12707 if (!LF && !RF)
12708 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes);
12709 else if (!LF)
12710 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12711 << getAsBaseClass(LHSDesignator.Entries[Mismatch])
12712 << RF->getParent() << RF;
12713 else if (!RF)
12714 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field)
12715 << getAsBaseClass(RHSDesignator.Entries[Mismatch])
12716 << LF->getParent() << LF;
12717 else if (!LF->getParent()->isUnion() &&
12718 LF->getAccess() != RF->getAccess())
12719 Info.CCEDiag(E,
12720 diag::note_constexpr_pointer_comparison_differing_access)
12721 << LF << LF->getAccess() << RF << RF->getAccess()
12722 << LF->getParent();
12723 }
12724 }
12725
12726 // The comparison here must be unsigned, and performed with the same
12727 // width as the pointer.
12728 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy);
12729 uint64_t CompareLHS = LHSOffset.getQuantity();
12730 uint64_t CompareRHS = RHSOffset.getQuantity();
12731 assert(PtrSize <= 64 && "Unexpected pointer width");
12732 uint64_t Mask = ~0ULL >> (64 - PtrSize);
12733 CompareLHS &= Mask;
12734 CompareRHS &= Mask;
12735
12736 // If there is a base and this is a relational operator, we can only
12737 // compare pointers within the object in question; otherwise, the result
12738 // depends on where the object is located in memory.
12739 if (!LHSValue.Base.isNull() && IsRelational) {
12740 QualType BaseTy = getType(LHSValue.Base);
12741 if (BaseTy->isIncompleteType())
12742 return Error(E);
12743 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy);
12744 uint64_t OffsetLimit = Size.getQuantity();
12745 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit)
12746 return Error(E);
12747 }
12748
12749 if (CompareLHS < CompareRHS)
12750 return Success(CmpResult::Less, E);
12751 if (CompareLHS > CompareRHS)
12752 return Success(CmpResult::Greater, E);
12753 return Success(CmpResult::Equal, E);
12754 }
12755
12756 if (LHSTy->isMemberPointerType()) {
12757 assert(IsEquality && "unexpected member pointer operation");
12758 assert(RHSTy->isMemberPointerType() && "invalid comparison");
12759
12760 MemberPtr LHSValue, RHSValue;
12761
12762 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info);
12763 if (!LHSOK && !Info.noteFailure())
12764 return false;
12765
12766 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12767 return false;
12768
12769 // C++11 [expr.eq]p2:
12770 // If both operands are null, they compare equal. Otherwise if only one is
12771 // null, they compare unequal.
12772 if (!LHSValue.getDecl() || !RHSValue.getDecl()) {
12773 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl();
12774 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12775 }
12776
12777 // Otherwise if either is a pointer to a virtual member function, the
12778 // result is unspecified.
12779 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl()))
12780 if (MD->isVirtual())
12781 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12782 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl()))
12783 if (MD->isVirtual())
12784 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD;
12785
12786 // Otherwise they compare equal if and only if they would refer to the
12787 // same member of the same most derived object or the same subobject if
12788 // they were dereferenced with a hypothetical object of the associated
12789 // class type.
12790 bool Equal = LHSValue == RHSValue;
12791 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E);
12792 }
12793
12794 if (LHSTy->isNullPtrType()) {
12795 assert(E->isComparisonOp() && "unexpected nullptr operation");
12796 assert(RHSTy->isNullPtrType() && "missing pointer conversion");
12797 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t
12798 // are compared, the result is true of the operator is <=, >= or ==, and
12799 // false otherwise.
12800 return Success(CmpResult::Equal, E);
12801 }
12802
12803 return DoAfter();
12804}
12805
12806bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) {
12807 if (!CheckLiteralType(Info, E))
12808 return false;
12809
12810 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12811 ComparisonCategoryResult CCR;
12812 switch (CR) {
12813 case CmpResult::Unequal:
12814 llvm_unreachable("should never produce Unequal for three-way comparison");
12815 case CmpResult::Less:
12816 CCR = ComparisonCategoryResult::Less;
12817 break;
12818 case CmpResult::Equal:
12819 CCR = ComparisonCategoryResult::Equal;
12820 break;
12821 case CmpResult::Greater:
12822 CCR = ComparisonCategoryResult::Greater;
12823 break;
12824 case CmpResult::Unordered:
12825 CCR = ComparisonCategoryResult::Unordered;
12826 break;
12827 }
12828 // Evaluation succeeded. Lookup the information for the comparison category
12829 // type and fetch the VarDecl for the result.
12830 const ComparisonCategoryInfo &CmpInfo =
12831 Info.Ctx.CompCategories.getInfoForType(E->getType());
12832 const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD;
12833 // Check and evaluate the result as a constant expression.
12834 LValue LV;
12835 LV.set(VD);
12836 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
12837 return false;
12838 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
12839 ConstantExprKind::Normal);
12840 };
12841 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12842 return ExprEvaluatorBaseTy::VisitBinCmp(E);
12843 });
12844}
12845
12846bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
12847 // We don't call noteFailure immediately because the assignment happens after
12848 // we evaluate LHS and RHS.
12849 if (!Info.keepEvaluatingAfterFailure() && E->isAssignmentOp())
12850 return Error(E);
12851
12852 DelayedNoteFailureRAII MaybeNoteFailureLater(Info, E->isAssignmentOp());
12853 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E))
12854 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E);
12855
12856 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() ||
12857 !E->getRHS()->getType()->isIntegralOrEnumerationType()) &&
12858 "DataRecursiveIntBinOpEvaluator should have handled integral types");
12859
12860 if (E->isComparisonOp()) {
12861 // Evaluate builtin binary comparisons by evaluating them as three-way
12862 // comparisons and then translating the result.
12863 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) {
12864 assert((CR != CmpResult::Unequal || E->isEqualityOp()) &&
12865 "should only produce Unequal for equality comparisons");
12866 bool IsEqual = CR == CmpResult::Equal,
12867 IsLess = CR == CmpResult::Less,
12868 IsGreater = CR == CmpResult::Greater;
12869 auto Op = E->getOpcode();
12870 switch (Op) {
12871 default:
12872 llvm_unreachable("unsupported binary operator");
12873 case BO_EQ:
12874 case BO_NE:
12875 return Success(IsEqual == (Op == BO_EQ), E);
12876 case BO_LT:
12877 return Success(IsLess, E);
12878 case BO_GT:
12879 return Success(IsGreater, E);
12880 case BO_LE:
12881 return Success(IsEqual || IsLess, E);
12882 case BO_GE:
12883 return Success(IsEqual || IsGreater, E);
12884 }
12885 };
12886 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() {
12887 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12888 });
12889 }
12890
12891 QualType LHSTy = E->getLHS()->getType();
12892 QualType RHSTy = E->getRHS()->getType();
12893
12894 if (LHSTy->isPointerType() && RHSTy->isPointerType() &&
12895 E->getOpcode() == BO_Sub) {
12896 LValue LHSValue, RHSValue;
12897
12898 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info);
12899 if (!LHSOK && !Info.noteFailure())
12900 return false;
12901
12902 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK)
12903 return false;
12904
12905 // Reject differing bases from the normal codepath; we special-case
12906 // comparisons to null.
12907 if (!HasSameBase(LHSValue, RHSValue)) {
12908 // Handle &&A - &&B.
12909 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero())
12910 return Error(E);
12911 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>();
12912 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>();
12913 if (!LHSExpr || !RHSExpr)
12914 return Error(E);
12915 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr);
12916 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr);
12917 if (!LHSAddrExpr || !RHSAddrExpr)
12918 return Error(E);
12919 // Make sure both labels come from the same function.
12920 if (LHSAddrExpr->getLabel()->getDeclContext() !=
12921 RHSAddrExpr->getLabel()->getDeclContext())
12922 return Error(E);
12923 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E);
12924 }
12925 const CharUnits &LHSOffset = LHSValue.getLValueOffset();
12926 const CharUnits &RHSOffset = RHSValue.getLValueOffset();
12927
12928 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator();
12929 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator();
12930
12931 // C++11 [expr.add]p6:
12932 // Unless both pointers point to elements of the same array object, or
12933 // one past the last element of the array object, the behavior is
12934 // undefined.
12935 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid &&
12936 !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator,
12937 RHSDesignator))
12938 Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array);
12939
12940 QualType Type = E->getLHS()->getType();
12941 QualType ElementType = Type->castAs<PointerType>()->getPointeeType();
12942
12943 CharUnits ElementSize;
12944 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize))
12945 return false;
12946
12947 // As an extension, a type may have zero size (empty struct or union in
12948 // C, array of zero length). Pointer subtraction in such cases has
12949 // undefined behavior, so is not constant.
12950 if (ElementSize.isZero()) {
12951 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size)
12952 << ElementType;
12953 return false;
12954 }
12955
12956 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime,
12957 // and produce incorrect results when it overflows. Such behavior
12958 // appears to be non-conforming, but is common, so perhaps we should
12959 // assume the standard intended for such cases to be undefined behavior
12960 // and check for them.
12961
12962 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for
12963 // overflow in the final conversion to ptrdiff_t.
12964 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false);
12965 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false);
12966 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true),
12967 false);
12968 APSInt TrueResult = (LHS - RHS) / ElemSize;
12969 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType()));
12970
12971 if (Result.extend(65) != TrueResult &&
12972 !HandleOverflow(Info, E, TrueResult, E->getType()))
12973 return false;
12974 return Success(Result, E);
12975 }
12976
12977 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
12978}
12979
12980/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with
12981/// a result as the expression's type.
12982bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr(
12983 const UnaryExprOrTypeTraitExpr *E) {
12984 switch(E->getKind()) {
12985 case UETT_PreferredAlignOf:
12986 case UETT_AlignOf: {
12987 if (E->isArgumentType())
12988 return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()),
12989 E);
12990 else
12991 return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()),
12992 E);
12993 }
12994
12995 case UETT_VecStep: {
12996 QualType Ty = E->getTypeOfArgument();
12997
12998 if (Ty->isVectorType()) {
12999 unsigned n = Ty->castAs<VectorType>()->getNumElements();
13000
13001 // The vec_step built-in functions that take a 3-component
13002 // vector return 4. (OpenCL 1.1 spec 6.11.12)
13003 if (n == 3)
13004 n = 4;
13005
13006 return Success(n, E);
13007 } else
13008 return Success(1, E);
13009 }
13010
13011 case UETT_SizeOf: {
13012 QualType SrcTy = E->getTypeOfArgument();
13013 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type,
13014 // the result is the size of the referenced type."
13015 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>())
13016 SrcTy = Ref->getPointeeType();
13017
13018 CharUnits Sizeof;
13019 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof))
13020 return false;
13021 return Success(Sizeof, E);
13022 }
13023 case UETT_OpenMPRequiredSimdAlign:
13024 assert(E->isArgumentType());
13025 return Success(
13026 Info.Ctx.toCharUnitsFromBits(
13027 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType()))
13028 .getQuantity(),
13029 E);
13030 }
13031
13032 llvm_unreachable("unknown expr/type trait");
13033}
13034
13035bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) {
13036 CharUnits Result;
13037 unsigned n = OOE->getNumComponents();
13038 if (n == 0)
13039 return Error(OOE);
13040 QualType CurrentType = OOE->getTypeSourceInfo()->getType();
13041 for (unsigned i = 0; i != n; ++i) {
13042 OffsetOfNode ON = OOE->getComponent(i);
13043 switch (ON.getKind()) {
13044 case OffsetOfNode::Array: {
13045 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex());
13046 APSInt IdxResult;
13047 if (!EvaluateInteger(Idx, IdxResult, Info))
13048 return false;
13049 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType);
13050 if (!AT)
13051 return Error(OOE);
13052 CurrentType = AT->getElementType();
13053 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType);
13054 Result += IdxResult.getSExtValue() * ElementSize;
13055 break;
13056 }
13057
13058 case OffsetOfNode::Field: {
13059 FieldDecl *MemberDecl = ON.getField();
13060 const RecordType *RT = CurrentType->getAs<RecordType>();
13061 if (!RT)
13062 return Error(OOE);
13063 RecordDecl *RD = RT->getDecl();
13064 if (RD->isInvalidDecl()) return false;
13065 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
13066 unsigned i = MemberDecl->getFieldIndex();
13067 assert(i < RL.getFieldCount() && "offsetof field in wrong type");
13068 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i));
13069 CurrentType = MemberDecl->getType().getNonReferenceType();
13070 break;
13071 }
13072
13073 case OffsetOfNode::Identifier:
13074 llvm_unreachable("dependent __builtin_offsetof");
13075
13076 case OffsetOfNode::Base: {
13077 CXXBaseSpecifier *BaseSpec = ON.getBase();
13078 if (BaseSpec->isVirtual())
13079 return Error(OOE);
13080
13081 // Find the layout of the class whose base we are looking into.
13082 const RecordType *RT = CurrentType->getAs<RecordType>();
13083 if (!RT)
13084 return Error(OOE);
13085 RecordDecl *RD = RT->getDecl();
13086 if (RD->isInvalidDecl()) return false;
13087 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD);
13088
13089 // Find the base class itself.
13090 CurrentType = BaseSpec->getType();
13091 const RecordType *BaseRT = CurrentType->getAs<RecordType>();
13092 if (!BaseRT)
13093 return Error(OOE);
13094
13095 // Add the offset to the base.
13096 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
13097 break;
13098 }
13099 }
13100 }
13101 return Success(Result, OOE);
13102}
13103
13104bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13105 switch (E->getOpcode()) {
13106 default:
13107 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs.
13108 // See C99 6.6p3.
13109 return Error(E);
13110 case UO_Extension:
13111 // FIXME: Should extension allow i-c-e extension expressions in its scope?
13112 // If so, we could clear the diagnostic ID.
13113 return Visit(E->getSubExpr());
13114 case UO_Plus:
13115 // The result is just the value.
13116 return Visit(E->getSubExpr());
13117 case UO_Minus: {
13118 if (!Visit(E->getSubExpr()))
13119 return false;
13120 if (!Result.isInt()) return Error(E);
13121 const APSInt &Value = Result.getInt();
13122 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() &&
13123 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1),
13124 E->getType()))
13125 return false;
13126 return Success(-Value, E);
13127 }
13128 case UO_Not: {
13129 if (!Visit(E->getSubExpr()))
13130 return false;
13131 if (!Result.isInt()) return Error(E);
13132 return Success(~Result.getInt(), E);
13133 }
13134 case UO_LNot: {
13135 bool bres;
13136 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
13137 return false;
13138 return Success(!bres, E);
13139 }
13140 }
13141}
13142
13143/// HandleCast - This is used to evaluate implicit or explicit casts where the
13144/// result type is integer.
13145bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
13146 const Expr *SubExpr = E->getSubExpr();
13147 QualType DestType = E->getType();
13148 QualType SrcType = SubExpr->getType();
13149
13150 switch (E->getCastKind()) {
13151 case CK_BaseToDerived:
13152 case CK_DerivedToBase:
13153 case CK_UncheckedDerivedToBase:
13154 case CK_Dynamic:
13155 case CK_ToUnion:
13156 case CK_ArrayToPointerDecay:
13157 case CK_FunctionToPointerDecay:
13158 case CK_NullToPointer:
13159 case CK_NullToMemberPointer:
13160 case CK_BaseToDerivedMemberPointer:
13161 case CK_DerivedToBaseMemberPointer:
13162 case CK_ReinterpretMemberPointer:
13163 case CK_ConstructorConversion:
13164 case CK_IntegralToPointer:
13165 case CK_ToVoid:
13166 case CK_VectorSplat:
13167 case CK_IntegralToFloating:
13168 case CK_FloatingCast:
13169 case CK_CPointerToObjCPointerCast:
13170 case CK_BlockPointerToObjCPointerCast:
13171 case CK_AnyPointerToBlockPointerCast:
13172 case CK_ObjCObjectLValueCast:
13173 case CK_FloatingRealToComplex:
13174 case CK_FloatingComplexToReal:
13175 case CK_FloatingComplexCast:
13176 case CK_FloatingComplexToIntegralComplex:
13177 case CK_IntegralRealToComplex:
13178 case CK_IntegralComplexCast:
13179 case CK_IntegralComplexToFloatingComplex:
13180 case CK_BuiltinFnToFnPtr:
13181 case CK_ZeroToOCLOpaqueType:
13182 case CK_NonAtomicToAtomic:
13183 case CK_AddressSpaceConversion:
13184 case CK_IntToOCLSampler:
13185 case CK_FloatingToFixedPoint:
13186 case CK_FixedPointToFloating:
13187 case CK_FixedPointCast:
13188 case CK_IntegralToFixedPoint:
13189 llvm_unreachable("invalid cast kind for integral value");
13190
13191 case CK_BitCast:
13192 case CK_Dependent:
13193 case CK_LValueBitCast:
13194 case CK_ARCProduceObject:
13195 case CK_ARCConsumeObject:
13196 case CK_ARCReclaimReturnedObject:
13197 case CK_ARCExtendBlockObject:
13198 case CK_CopyAndAutoreleaseBlockObject:
13199 return Error(E);
13200
13201 case CK_UserDefinedConversion:
13202 case CK_LValueToRValue:
13203 case CK_AtomicToNonAtomic:
13204 case CK_NoOp:
13205 case CK_LValueToRValueBitCast:
13206 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13207
13208 case CK_MemberPointerToBoolean:
13209 case CK_PointerToBoolean:
13210 case CK_IntegralToBoolean:
13211 case CK_FloatingToBoolean:
13212 case CK_BooleanToSignedIntegral:
13213 case CK_FloatingComplexToBoolean:
13214 case CK_IntegralComplexToBoolean: {
13215 bool BoolResult;
13216 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info))
13217 return false;
13218 uint64_t IntResult = BoolResult;
13219 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral)
13220 IntResult = (uint64_t)-1;
13221 return Success(IntResult, E);
13222 }
13223
13224 case CK_FixedPointToIntegral: {
13225 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType));
13226 if (!EvaluateFixedPoint(SubExpr, Src, Info))
13227 return false;
13228 bool Overflowed;
13229 llvm::APSInt Result = Src.convertToInt(
13230 Info.Ctx.getIntWidth(DestType),
13231 DestType->isSignedIntegerOrEnumerationType(), &Overflowed);
13232 if (Overflowed && !HandleOverflow(Info, E, Result, DestType))
13233 return false;
13234 return Success(Result, E);
13235 }
13236
13237 case CK_FixedPointToBoolean: {
13238 // Unsigned padding does not affect this.
13239 APValue Val;
13240 if (!Evaluate(Val, Info, SubExpr))
13241 return false;
13242 return Success(Val.getFixedPoint().getBoolValue(), E);
13243 }
13244
13245 case CK_IntegralCast: {
13246 if (!Visit(SubExpr))
13247 return false;
13248
13249 if (!Result.isInt()) {
13250 // Allow casts of address-of-label differences if they are no-ops
13251 // or narrowing. (The narrowing case isn't actually guaranteed to
13252 // be constant-evaluatable except in some narrow cases which are hard
13253 // to detect here. We let it through on the assumption the user knows
13254 // what they are doing.)
13255 if (Result.isAddrLabelDiff())
13256 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType);
13257 // Only allow casts of lvalues if they are lossless.
13258 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType);
13259 }
13260
13261 return Success(HandleIntToIntCast(Info, E, DestType, SrcType,
13262 Result.getInt()), E);
13263 }
13264
13265 case CK_PointerToIntegral: {
13266 CCEDiag(E, diag::note_constexpr_invalid_cast) << 2;
13267
13268 LValue LV;
13269 if (!EvaluatePointer(SubExpr, LV, Info))
13270 return false;
13271
13272 if (LV.getLValueBase()) {
13273 // Only allow based lvalue casts if they are lossless.
13274 // FIXME: Allow a larger integer size than the pointer size, and allow
13275 // narrowing back down to pointer width in subsequent integral casts.
13276 // FIXME: Check integer type's active bits, not its type size.
13277 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
13278 return Error(E);
13279
13280 LV.Designator.setInvalid();
13281 LV.moveInto(Result);
13282 return true;
13283 }
13284
13285 APSInt AsInt;
13286 APValue V;
13287 LV.moveInto(V);
13288 if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx))
13289 llvm_unreachable("Can't cast this!");
13290
13291 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
13292 }
13293
13294 case CK_IntegralComplexToReal: {
13295 ComplexValue C;
13296 if (!EvaluateComplex(SubExpr, C, Info))
13297 return false;
13298 return Success(C.getComplexIntReal(), E);
13299 }
13300
13301 case CK_FloatingToIntegral: {
13302 APFloat F(0.0);
13303 if (!EvaluateFloat(SubExpr, F, Info))
13304 return false;
13305
13306 APSInt Value;
13307 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value))
13308 return false;
13309 return Success(Value, E);
13310 }
13311 }
13312
13313 llvm_unreachable("unknown cast resulting in integral value");
13314}
13315
13316bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
13317 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13318 ComplexValue LV;
13319 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
13320 return false;
13321 if (!LV.isComplexInt())
13322 return Error(E);
13323 return Success(LV.getComplexIntReal(), E);
13324 }
13325
13326 return Visit(E->getSubExpr());
13327}
13328
13329bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
13330 if (E->getSubExpr()->getType()->isComplexIntegerType()) {
13331 ComplexValue LV;
13332 if (!EvaluateComplex(E->getSubExpr(), LV, Info))
13333 return false;
13334 if (!LV.isComplexInt())
13335 return Error(E);
13336 return Success(LV.getComplexIntImag(), E);
13337 }
13338
13339 VisitIgnoredValue(E->getSubExpr());
13340 return Success(0, E);
13341}
13342
13343bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) {
13344 return Success(E->getPackLength(), E);
13345}
13346
13347bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) {
13348 return Success(E->getValue(), E);
13349}
13350
13351bool IntExprEvaluator::VisitConceptSpecializationExpr(
13352 const ConceptSpecializationExpr *E) {
13353 return Success(E->isSatisfied(), E);
13354}
13355
13356bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) {
13357 return Success(E->isSatisfied(), E);
13358}
13359
13360bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13361 switch (E->getOpcode()) {
13362 default:
13363 // Invalid unary operators
13364 return Error(E);
13365 case UO_Plus:
13366 // The result is just the value.
13367 return Visit(E->getSubExpr());
13368 case UO_Minus: {
13369 if (!Visit(E->getSubExpr())) return false;
13370 if (!Result.isFixedPoint())
13371 return Error(E);
13372 bool Overflowed;
13373 APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed);
13374 if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType()))
13375 return false;
13376 return Success(Negated, E);
13377 }
13378 case UO_LNot: {
13379 bool bres;
13380 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info))
13381 return false;
13382 return Success(!bres, E);
13383 }
13384 }
13385}
13386
13387bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) {
13388 const Expr *SubExpr = E->getSubExpr();
13389 QualType DestType = E->getType();
13390 assert(DestType->isFixedPointType() &&
13391 "Expected destination type to be a fixed point type");
13392 auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType);
13393
13394 switch (E->getCastKind()) {
13395 case CK_FixedPointCast: {
13396 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
13397 if (!EvaluateFixedPoint(SubExpr, Src, Info))
13398 return false;
13399 bool Overflowed;
13400 APFixedPoint Result = Src.convert(DestFXSema, &Overflowed);
13401 if (Overflowed) {
13402 if (Info.checkingForUndefinedBehavior())
13403 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13404 diag::warn_fixedpoint_constant_overflow)
13405 << Result.toString() << E->getType();
13406 else if (!HandleOverflow(Info, E, Result, E->getType()))
13407 return false;
13408 }
13409 return Success(Result, E);
13410 }
13411 case CK_IntegralToFixedPoint: {
13412 APSInt Src;
13413 if (!EvaluateInteger(SubExpr, Src, Info))
13414 return false;
13415
13416 bool Overflowed;
13417 APFixedPoint IntResult = APFixedPoint::getFromIntValue(
13418 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);
13419
13420 if (Overflowed) {
13421 if (Info.checkingForUndefinedBehavior())
13422 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13423 diag::warn_fixedpoint_constant_overflow)
13424 << IntResult.toString() << E->getType();
13425 else if (!HandleOverflow(Info, E, IntResult, E->getType()))
13426 return false;
13427 }
13428
13429 return Success(IntResult, E);
13430 }
13431 case CK_FloatingToFixedPoint: {
13432 APFloat Src(0.0);
13433 if (!EvaluateFloat(SubExpr, Src, Info))
13434 return false;
13435
13436 bool Overflowed;
13437 APFixedPoint Result = APFixedPoint::getFromFloatValue(
13438 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed);
13439
13440 if (Overflowed) {
13441 if (Info.checkingForUndefinedBehavior())
13442 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13443 diag::warn_fixedpoint_constant_overflow)
13444 << Result.toString() << E->getType();
13445 else if (!HandleOverflow(Info, E, Result, E->getType()))
13446 return false;
13447 }
13448
13449 return Success(Result, E);
13450 }
13451 case CK_NoOp:
13452 case CK_LValueToRValue:
13453 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13454 default:
13455 return Error(E);
13456 }
13457}
13458
13459bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13460 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13461 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13462
13463 const Expr *LHS = E->getLHS();
13464 const Expr *RHS = E->getRHS();
13465 FixedPointSemantics ResultFXSema =
13466 Info.Ctx.getFixedPointSemantics(E->getType());
13467
13468 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType()));
13469 if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info))
13470 return false;
13471 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType()));
13472 if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info))
13473 return false;
13474
13475 bool OpOverflow = false, ConversionOverflow = false;
13476 APFixedPoint Result(LHSFX.getSemantics());
13477 switch (E->getOpcode()) {
13478 case BO_Add: {
13479 Result = LHSFX.add(RHSFX, &OpOverflow)
13480 .convert(ResultFXSema, &ConversionOverflow);
13481 break;
13482 }
13483 case BO_Sub: {
13484 Result = LHSFX.sub(RHSFX, &OpOverflow)
13485 .convert(ResultFXSema, &ConversionOverflow);
13486 break;
13487 }
13488 case BO_Mul: {
13489 Result = LHSFX.mul(RHSFX, &OpOverflow)
13490 .convert(ResultFXSema, &ConversionOverflow);
13491 break;
13492 }
13493 case BO_Div: {
13494 if (RHSFX.getValue() == 0) {
13495 Info.FFDiag(E, diag::note_expr_divide_by_zero);
13496 return false;
13497 }
13498 Result = LHSFX.div(RHSFX, &OpOverflow)
13499 .convert(ResultFXSema, &ConversionOverflow);
13500 break;
13501 }
13502 case BO_Shl:
13503 case BO_Shr: {
13504 FixedPointSemantics LHSSema = LHSFX.getSemantics();
13505 llvm::APSInt RHSVal = RHSFX.getValue();
13506
13507 unsigned ShiftBW =
13508 LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding();
13509 unsigned Amt = RHSVal.getLimitedValue(ShiftBW - 1);
13510 // Embedded-C 4.1.6.2.2:
13511 // The right operand must be nonnegative and less than the total number
13512 // of (nonpadding) bits of the fixed-point operand ...
13513 if (RHSVal.isNegative())
13514 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHSVal;
13515 else if (Amt != RHSVal)
13516 Info.CCEDiag(E, diag::note_constexpr_large_shift)
13517 << RHSVal << E->getType() << ShiftBW;
13518
13519 if (E->getOpcode() == BO_Shl)
13520 Result = LHSFX.shl(Amt, &OpOverflow);
13521 else
13522 Result = LHSFX.shr(Amt, &OpOverflow);
13523 break;
13524 }
13525 default:
13526 return false;
13527 }
13528 if (OpOverflow || ConversionOverflow) {
13529 if (Info.checkingForUndefinedBehavior())
13530 Info.Ctx.getDiagnostics().Report(E->getExprLoc(),
13531 diag::warn_fixedpoint_constant_overflow)
13532 << Result.toString() << E->getType();
13533 else if (!HandleOverflow(Info, E, Result, E->getType()))
13534 return false;
13535 }
13536 return Success(Result, E);
13537}
13538
13539//===----------------------------------------------------------------------===//
13540// Float Evaluation
13541//===----------------------------------------------------------------------===//
13542
13543namespace {
13544class FloatExprEvaluator
13545 : public ExprEvaluatorBase<FloatExprEvaluator> {
13546 APFloat &Result;
13547public:
13548 FloatExprEvaluator(EvalInfo &info, APFloat &result)
13549 : ExprEvaluatorBaseTy(info), Result(result) {}
13550
13551 bool Success(const APValue &V, const Expr *e) {
13552 Result = V.getFloat();
13553 return true;
13554 }
13555
13556 bool ZeroInitialization(const Expr *E) {
13557 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType()));
13558 return true;
13559 }
13560
13561 bool VisitCallExpr(const CallExpr *E);
13562
13563 bool VisitUnaryOperator(const UnaryOperator *E);
13564 bool VisitBinaryOperator(const BinaryOperator *E);
13565 bool VisitFloatingLiteral(const FloatingLiteral *E);
13566 bool VisitCastExpr(const CastExpr *E);
13567
13568 bool VisitUnaryReal(const UnaryOperator *E);
13569 bool VisitUnaryImag(const UnaryOperator *E);
13570
13571 // FIXME: Missing: array subscript of vector, member of vector
13572};
13573} // end anonymous namespace
13574
13575static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) {
13576 assert(!E->isValueDependent());
13577 assert(E->isRValue() && E->getType()->isRealFloatingType());
13578 return FloatExprEvaluator(Info, Result).Visit(E);
13579}
13580
13581static bool TryEvaluateBuiltinNaN(const ASTContext &Context,
13582 QualType ResultTy,
13583 const Expr *Arg,
13584 bool SNaN,
13585 llvm::APFloat &Result) {
13586 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts());
13587 if (!S) return false;
13588
13589 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy);
13590
13591 llvm::APInt fill;
13592
13593 // Treat empty strings as if they were zero.
13594 if (S->getString().empty())
13595 fill = llvm::APInt(32, 0);
13596 else if (S->getString().getAsInteger(0, fill))
13597 return false;
13598
13599 if (Context.getTargetInfo().isNan2008()) {
13600 if (SNaN)
13601 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13602 else
13603 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13604 } else {
13605 // Prior to IEEE 754-2008, architectures were allowed to choose whether
13606 // the first bit of their significand was set for qNaN or sNaN. MIPS chose
13607 // a different encoding to what became a standard in 2008, and for pre-
13608 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as
13609 // sNaN. This is now known as "legacy NaN" encoding.
13610 if (SNaN)
13611 Result = llvm::APFloat::getQNaN(Sem, false, &fill);
13612 else
13613 Result = llvm::APFloat::getSNaN(Sem, false, &fill);
13614 }
13615
13616 return true;
13617}
13618
13619bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
13620 switch (E->getBuiltinCallee()) {
13621 default:
13622 return ExprEvaluatorBaseTy::VisitCallExpr(E);
13623
13624 case Builtin::BI__builtin_huge_val:
13625 case Builtin::BI__builtin_huge_valf:
13626 case Builtin::BI__builtin_huge_vall:
13627 case Builtin::BI__builtin_huge_valf128:
13628 case Builtin::BI__builtin_inf:
13629 case Builtin::BI__builtin_inff:
13630 case Builtin::BI__builtin_infl:
13631 case Builtin::BI__builtin_inff128: {
13632 const llvm::fltSemantics &Sem =
13633 Info.Ctx.getFloatTypeSemantics(E->getType());
13634 Result = llvm::APFloat::getInf(Sem);
13635 return true;
13636 }
13637
13638 case Builtin::BI__builtin_nans:
13639 case Builtin::BI__builtin_nansf:
13640 case Builtin::BI__builtin_nansl:
13641 case Builtin::BI__builtin_nansf128:
13642 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13643 true, Result))
13644 return Error(E);
13645 return true;
13646
13647 case Builtin::BI__builtin_nan:
13648 case Builtin::BI__builtin_nanf:
13649 case Builtin::BI__builtin_nanl:
13650 case Builtin::BI__builtin_nanf128:
13651 // If this is __builtin_nan() turn this into a nan, otherwise we
13652 // can't constant fold it.
13653 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0),
13654 false, Result))
13655 return Error(E);
13656 return true;
13657
13658 case Builtin::BI__builtin_fabs:
13659 case Builtin::BI__builtin_fabsf:
13660 case Builtin::BI__builtin_fabsl:
13661 case Builtin::BI__builtin_fabsf128:
13662 // The C standard says "fabs raises no floating-point exceptions,
13663 // even if x is a signaling NaN. The returned value is independent of
13664 // the current rounding direction mode." Therefore constant folding can
13665 // proceed without regard to the floating point settings.
13666 // Reference, WG14 N2478 F.10.4.3
13667 if (!EvaluateFloat(E->getArg(0), Result, Info))
13668 return false;
13669
13670 if (Result.isNegative())
13671 Result.changeSign();
13672 return true;
13673
13674 // FIXME: Builtin::BI__builtin_powi
13675 // FIXME: Builtin::BI__builtin_powif
13676 // FIXME: Builtin::BI__builtin_powil
13677
13678 case Builtin::BI__builtin_copysign:
13679 case Builtin::BI__builtin_copysignf:
13680 case Builtin::BI__builtin_copysignl:
13681 case Builtin::BI__builtin_copysignf128: {
13682 APFloat RHS(0.);
13683 if (!EvaluateFloat(E->getArg(0), Result, Info) ||
13684 !EvaluateFloat(E->getArg(1), RHS, Info))
13685 return false;
13686 Result.copySign(RHS);
13687 return true;
13688 }
13689 }
13690}
13691
13692bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
13693 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13694 ComplexValue CV;
13695 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13696 return false;
13697 Result = CV.FloatReal;
13698 return true;
13699 }
13700
13701 return Visit(E->getSubExpr());
13702}
13703
13704bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
13705 if (E->getSubExpr()->getType()->isAnyComplexType()) {
13706 ComplexValue CV;
13707 if (!EvaluateComplex(E->getSubExpr(), CV, Info))
13708 return false;
13709 Result = CV.FloatImag;
13710 return true;
13711 }
13712
13713 VisitIgnoredValue(E->getSubExpr());
13714 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType());
13715 Result = llvm::APFloat::getZero(Sem);
13716 return true;
13717}
13718
13719bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
13720 switch (E->getOpcode()) {
13721 default: return Error(E);
13722 case UO_Plus:
13723 return EvaluateFloat(E->getSubExpr(), Result, Info);
13724 case UO_Minus:
13725 // In C standard, WG14 N2478 F.3 p4
13726 // "the unary - raises no floating point exceptions,
13727 // even if the operand is signalling."
13728 if (!EvaluateFloat(E->getSubExpr(), Result, Info))
13729 return false;
13730 Result.changeSign();
13731 return true;
13732 }
13733}
13734
13735bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
13736 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
13737 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
13738
13739 APFloat RHS(0.0);
13740 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info);
13741 if (!LHSOK && !Info.noteFailure())
13742 return false;
13743 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK &&
13744 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS);
13745}
13746
13747bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) {
13748 Result = E->getValue();
13749 return true;
13750}
13751
13752bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) {
13753 const Expr* SubExpr = E->getSubExpr();
13754
13755 switch (E->getCastKind()) {
13756 default:
13757 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13758
13759 case CK_IntegralToFloating: {
13760 APSInt IntResult;
13761 const FPOptions FPO = E->getFPFeaturesInEffect(
13762 Info.Ctx.getLangOpts());
13763 return EvaluateInteger(SubExpr, IntResult, Info) &&
13764 HandleIntToFloatCast(Info, E, FPO, SubExpr->getType(),
13765 IntResult, E->getType(), Result);
13766 }
13767
13768 case CK_FixedPointToFloating: {
13769 APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(SubExpr->getType()));
13770 if (!EvaluateFixedPoint(SubExpr, FixResult, Info))
13771 return false;
13772 Result =
13773 FixResult.convertToFloat(Info.Ctx.getFloatTypeSemantics(E->getType()));
13774 return true;
13775 }
13776
13777 case CK_FloatingCast: {
13778 if (!Visit(SubExpr))
13779 return false;
13780 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(),
13781 Result);
13782 }
13783
13784 case CK_FloatingComplexToReal: {
13785 ComplexValue V;
13786 if (!EvaluateComplex(SubExpr, V, Info))
13787 return false;
13788 Result = V.getComplexFloatReal();
13789 return true;
13790 }
13791 }
13792}
13793
13794//===----------------------------------------------------------------------===//
13795// Complex Evaluation (for float and integer)
13796//===----------------------------------------------------------------------===//
13797
13798namespace {
13799class ComplexExprEvaluator
13800 : public ExprEvaluatorBase<ComplexExprEvaluator> {
13801 ComplexValue &Result;
13802
13803public:
13804 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result)
13805 : ExprEvaluatorBaseTy(info), Result(Result) {}
13806
13807 bool Success(const APValue &V, const Expr *e) {
13808 Result.setFrom(V);
13809 return true;
13810 }
13811
13812 bool ZeroInitialization(const Expr *E);
13813
13814 //===--------------------------------------------------------------------===//
13815 // Visitor Methods
13816 //===--------------------------------------------------------------------===//
13817
13818 bool VisitImaginaryLiteral(const ImaginaryLiteral *E);
13819 bool VisitCastExpr(const CastExpr *E);
13820 bool VisitBinaryOperator(const BinaryOperator *E);
13821 bool VisitUnaryOperator(const UnaryOperator *E);
13822 bool VisitInitListExpr(const InitListExpr *E);
13823 bool VisitCallExpr(const CallExpr *E);
13824};
13825} // end anonymous namespace
13826
13827static bool EvaluateComplex(const Expr *E, ComplexValue &Result,
13828 EvalInfo &Info) {
13829 assert(!E->isValueDependent());
13830 assert(E->isRValue() && E->getType()->isAnyComplexType());
13831 return ComplexExprEvaluator(Info, Result).Visit(E);
13832}
13833
13834bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) {
13835 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType();
13836 if (ElemTy->isRealFloatingType()) {
13837 Result.makeComplexFloat();
13838 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy));
13839 Result.FloatReal = Zero;
13840 Result.FloatImag = Zero;
13841 } else {
13842 Result.makeComplexInt();
13843 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy);
13844 Result.IntReal = Zero;
13845 Result.IntImag = Zero;
13846 }
13847 return true;
13848}
13849
13850bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
13851 const Expr* SubExpr = E->getSubExpr();
13852
13853 if (SubExpr->getType()->isRealFloatingType()) {
13854 Result.makeComplexFloat();
13855 APFloat &Imag = Result.FloatImag;
13856 if (!EvaluateFloat(SubExpr, Imag, Info))
13857 return false;
13858
13859 Result.FloatReal = APFloat(Imag.getSemantics());
13860 return true;
13861 } else {
13862 assert(SubExpr->getType()->isIntegerType() &&
13863 "Unexpected imaginary literal.");
13864
13865 Result.makeComplexInt();
13866 APSInt &Imag = Result.IntImag;
13867 if (!EvaluateInteger(SubExpr, Imag, Info))
13868 return false;
13869
13870 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned());
13871 return true;
13872 }
13873}
13874
13875bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) {
13876
13877 switch (E->getCastKind()) {
13878 case CK_BitCast:
13879 case CK_BaseToDerived:
13880 case CK_DerivedToBase:
13881 case CK_UncheckedDerivedToBase:
13882 case CK_Dynamic:
13883 case CK_ToUnion:
13884 case CK_ArrayToPointerDecay:
13885 case CK_FunctionToPointerDecay:
13886 case CK_NullToPointer:
13887 case CK_NullToMemberPointer:
13888 case CK_BaseToDerivedMemberPointer:
13889 case CK_DerivedToBaseMemberPointer:
13890 case CK_MemberPointerToBoolean:
13891 case CK_ReinterpretMemberPointer:
13892 case CK_ConstructorConversion:
13893 case CK_IntegralToPointer:
13894 case CK_PointerToIntegral:
13895 case CK_PointerToBoolean:
13896 case CK_ToVoid:
13897 case CK_VectorSplat:
13898 case CK_IntegralCast:
13899 case CK_BooleanToSignedIntegral:
13900 case CK_IntegralToBoolean:
13901 case CK_IntegralToFloating:
13902 case CK_FloatingToIntegral:
13903 case CK_FloatingToBoolean:
13904 case CK_FloatingCast:
13905 case CK_CPointerToObjCPointerCast:
13906 case CK_BlockPointerToObjCPointerCast:
13907 case CK_AnyPointerToBlockPointerCast:
13908 case CK_ObjCObjectLValueCast:
13909 case CK_FloatingComplexToReal:
13910 case CK_FloatingComplexToBoolean:
13911 case CK_IntegralComplexToReal:
13912 case CK_IntegralComplexToBoolean:
13913 case CK_ARCProduceObject:
13914 case CK_ARCConsumeObject:
13915 case CK_ARCReclaimReturnedObject:
13916 case CK_ARCExtendBlockObject:
13917 case CK_CopyAndAutoreleaseBlockObject:
13918 case CK_BuiltinFnToFnPtr:
13919 case CK_ZeroToOCLOpaqueType:
13920 case CK_NonAtomicToAtomic:
13921 case CK_AddressSpaceConversion:
13922 case CK_IntToOCLSampler:
13923 case CK_FloatingToFixedPoint:
13924 case CK_FixedPointToFloating:
13925 case CK_FixedPointCast:
13926 case CK_FixedPointToBoolean:
13927 case CK_FixedPointToIntegral:
13928 case CK_IntegralToFixedPoint:
13929 llvm_unreachable("invalid cast kind for complex value");
13930
13931 case CK_LValueToRValue:
13932 case CK_AtomicToNonAtomic:
13933 case CK_NoOp:
13934 case CK_LValueToRValueBitCast:
13935 return ExprEvaluatorBaseTy::VisitCastExpr(E);
13936
13937 case CK_Dependent:
13938 case CK_LValueBitCast:
13939 case CK_UserDefinedConversion:
13940 return Error(E);
13941
13942 case CK_FloatingRealToComplex: {
13943 APFloat &Real = Result.FloatReal;
13944 if (!EvaluateFloat(E->getSubExpr(), Real, Info))
13945 return false;
13946
13947 Result.makeComplexFloat();
13948 Result.FloatImag = APFloat(Real.getSemantics());
13949 return true;
13950 }
13951
13952 case CK_FloatingComplexCast: {
13953 if (!Visit(E->getSubExpr()))
13954 return false;
13955
13956 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13957 QualType From
13958 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13959
13960 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) &&
13961 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag);
13962 }
13963
13964 case CK_FloatingComplexToIntegralComplex: {
13965 if (!Visit(E->getSubExpr()))
13966 return false;
13967
13968 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13969 QualType From
13970 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13971 Result.makeComplexInt();
13972 return HandleFloatToIntCast(Info, E, From, Result.FloatReal,
13973 To, Result.IntReal) &&
13974 HandleFloatToIntCast(Info, E, From, Result.FloatImag,
13975 To, Result.IntImag);
13976 }
13977
13978 case CK_IntegralRealToComplex: {
13979 APSInt &Real = Result.IntReal;
13980 if (!EvaluateInteger(E->getSubExpr(), Real, Info))
13981 return false;
13982
13983 Result.makeComplexInt();
13984 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned());
13985 return true;
13986 }
13987
13988 case CK_IntegralComplexCast: {
13989 if (!Visit(E->getSubExpr()))
13990 return false;
13991
13992 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
13993 QualType From
13994 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
13995
13996 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal);
13997 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag);
13998 return true;
13999 }
14000
14001 case CK_IntegralComplexToFloatingComplex: {
14002 if (!Visit(E->getSubExpr()))
14003 return false;
14004
14005 const FPOptions FPO = E->getFPFeaturesInEffect(
14006 Info.Ctx.getLangOpts());
14007 QualType To = E->getType()->castAs<ComplexType>()->getElementType();
14008 QualType From
14009 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType();
14010 Result.makeComplexFloat();
14011 return HandleIntToFloatCast(Info, E, FPO, From, Result.IntReal,
14012 To, Result.FloatReal) &&
14013 HandleIntToFloatCast(Info, E, FPO, From, Result.IntImag,
14014 To, Result.FloatImag);
14015 }
14016 }
14017
14018 llvm_unreachable("unknown cast resulting in complex value");
14019}
14020
14021bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
14022 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
14023 return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
14024
14025 // Track whether the LHS or RHS is real at the type system level. When this is
14026 // the case we can simplify our evaluation strategy.
14027 bool LHSReal = false, RHSReal = false;
14028
14029 bool LHSOK;
14030 if (E->getLHS()->getType()->isRealFloatingType()) {
14031 LHSReal = true;
14032 APFloat &Real = Result.FloatReal;
14033 LHSOK = EvaluateFloat(E->getLHS(), Real, Info);
14034 if (LHSOK) {
14035 Result.makeComplexFloat();
14036 Result.FloatImag = APFloat(Real.getSemantics());
14037 }
14038 } else {
14039 LHSOK = Visit(E->getLHS());
14040 }
14041 if (!LHSOK && !Info.noteFailure())
14042 return false;
14043
14044 ComplexValue RHS;
14045 if (E->getRHS()->getType()->isRealFloatingType()) {
14046 RHSReal = true;
14047 APFloat &Real = RHS.FloatReal;
14048 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK)
14049 return false;
14050 RHS.makeComplexFloat();
14051 RHS.FloatImag = APFloat(Real.getSemantics());
14052 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK)
14053 return false;
14054
14055 assert(!(LHSReal && RHSReal) &&
14056 "Cannot have both operands of a complex operation be real.");
14057 switch (E->getOpcode()) {
14058 default: return Error(E);
14059 case BO_Add:
14060 if (Result.isComplexFloat()) {
14061 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(),
14062 APFloat::rmNearestTiesToEven);
14063 if (LHSReal)
14064 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
14065 else if (!RHSReal)
14066 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(),
14067 APFloat::rmNearestTiesToEven);
14068 } else {
14069 Result.getComplexIntReal() += RHS.getComplexIntReal();
14070 Result.getComplexIntImag() += RHS.getComplexIntImag();
14071 }
14072 break;
14073 case BO_Sub:
14074 if (Result.isComplexFloat()) {
14075 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(),
14076 APFloat::rmNearestTiesToEven);
14077 if (LHSReal) {
14078 Result.getComplexFloatImag() = RHS.getComplexFloatImag();
14079 Result.getComplexFloatImag().changeSign();
14080 } else if (!RHSReal) {
14081 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(),
14082 APFloat::rmNearestTiesToEven);
14083 }
14084 } else {
14085 Result.getComplexIntReal() -= RHS.getComplexIntReal();
14086 Result.getComplexIntImag() -= RHS.getComplexIntImag();
14087 }
14088 break;
14089 case BO_Mul:
14090 if (Result.isComplexFloat()) {
14091 // This is an implementation of complex multiplication according to the
14092 // constraints laid out in C11 Annex G. The implementation uses the
14093 // following naming scheme:
14094 // (a + ib) * (c + id)
14095 ComplexValue LHS = Result;
14096 APFloat &A = LHS.getComplexFloatReal();
14097 APFloat &B = LHS.getComplexFloatImag();
14098 APFloat &C = RHS.getComplexFloatReal();
14099 APFloat &D = RHS.getComplexFloatImag();
14100 APFloat &ResR = Result.getComplexFloatReal();
14101 APFloat &ResI = Result.getComplexFloatImag();
14102 if (LHSReal) {
14103 assert(!RHSReal && "Cannot have two real operands for a complex op!");
14104 ResR = A * C;
14105 ResI = A * D;
14106 } else if (RHSReal) {
14107 ResR = C * A;
14108 ResI = C * B;
14109 } else {
14110 // In the fully general case, we need to handle NaNs and infinities
14111 // robustly.
14112 APFloat AC = A * C;
14113 APFloat BD = B * D;
14114 APFloat AD = A * D;
14115 APFloat BC = B * C;
14116 ResR = AC - BD;
14117 ResI = AD + BC;
14118 if (ResR.isNaN() && ResI.isNaN()) {
14119 bool Recalc = false;
14120 if (A.isInfinity() || B.isInfinity()) {
14121 A = APFloat::copySign(
14122 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
14123 B = APFloat::copySign(
14124 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
14125 if (C.isNaN())
14126 C = APFloat::copySign(APFloat(C.getSemantics()), C);
14127 if (D.isNaN())
14128 D = APFloat::copySign(APFloat(D.getSemantics()), D);
14129 Recalc = true;
14130 }
14131 if (C.isInfinity() || D.isInfinity()) {
14132 C = APFloat::copySign(
14133 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
14134 D = APFloat::copySign(
14135 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
14136 if (A.isNaN())
14137 A = APFloat::copySign(APFloat(A.getSemantics()), A);
14138 if (B.isNaN())
14139 B = APFloat::copySign(APFloat(B.getSemantics()), B);
14140 Recalc = true;
14141 }
14142 if (!Recalc && (AC.isInfinity() || BD.isInfinity() ||
14143 AD.isInfinity() || BC.isInfinity())) {
14144 if (A.isNaN())
14145 A = APFloat::copySign(APFloat(A.getSemantics()), A);
14146 if (B.isNaN())
14147 B = APFloat::copySign(APFloat(B.getSemantics()), B);
14148 if (C.isNaN())
14149 C = APFloat::copySign(APFloat(C.getSemantics()), C);
14150 if (D.isNaN())
14151 D = APFloat::copySign(APFloat(D.getSemantics()), D);
14152 Recalc = true;
14153 }
14154 if (Recalc) {
14155 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D);
14156 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C);
14157 }
14158 }
14159 }
14160 } else {
14161 ComplexValue LHS = Result;
14162 Result.getComplexIntReal() =
14163 (LHS.getComplexIntReal() * RHS.getComplexIntReal() -
14164 LHS.getComplexIntImag() * RHS.getComplexIntImag());
14165 Result.getComplexIntImag() =
14166 (LHS.getComplexIntReal() * RHS.getComplexIntImag() +
14167 LHS.getComplexIntImag() * RHS.getComplexIntReal());
14168 }
14169 break;
14170 case BO_Div:
14171 if (Result.isComplexFloat()) {
14172 // This is an implementation of complex division according to the
14173 // constraints laid out in C11 Annex G. The implementation uses the
14174 // following naming scheme:
14175 // (a + ib) / (c + id)
14176 ComplexValue LHS = Result;
14177 APFloat &A = LHS.getComplexFloatReal();
14178 APFloat &B = LHS.getComplexFloatImag();
14179 APFloat &C = RHS.getComplexFloatReal();
14180 APFloat &D = RHS.getComplexFloatImag();
14181 APFloat &ResR = Result.getComplexFloatReal();
14182 APFloat &ResI = Result.getComplexFloatImag();
14183 if (RHSReal) {
14184 ResR = A / C;
14185 ResI = B / C;
14186 } else {
14187 if (LHSReal) {
14188 // No real optimizations we can do here, stub out with zero.
14189 B = APFloat::getZero(A.getSemantics());
14190 }
14191 int DenomLogB = 0;
14192 APFloat MaxCD = maxnum(abs(C), abs(D));
14193 if (MaxCD.isFinite()) {
14194 DenomLogB = ilogb(MaxCD);
14195 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven);
14196 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven);
14197 }
14198 APFloat Denom = C * C + D * D;
14199 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB,
14200 APFloat::rmNearestTiesToEven);
14201 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB,
14202 APFloat::rmNearestTiesToEven);
14203 if (ResR.isNaN() && ResI.isNaN()) {
14204 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) {
14205 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A;
14206 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B;
14207 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() &&
14208 D.isFinite()) {
14209 A = APFloat::copySign(
14210 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A);
14211 B = APFloat::copySign(
14212 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B);
14213 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D);
14214 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D);
14215 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) {
14216 C = APFloat::copySign(
14217 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C);
14218 D = APFloat::copySign(
14219 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D);
14220 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D);
14221 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D);
14222 }
14223 }
14224 }
14225 } else {
14226 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0)
14227 return Error(E, diag::note_expr_divide_by_zero);
14228
14229 ComplexValue LHS = Result;
14230 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() +
14231 RHS.getComplexIntImag() * RHS.getComplexIntImag();
14232 Result.getComplexIntReal() =
14233 (LHS.getComplexIntReal() * RHS.getComplexIntReal() +
14234 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den;
14235 Result.getComplexIntImag() =
14236 (LHS.getComplexIntImag() * RHS.getComplexIntReal() -
14237 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den;
14238 }
14239 break;
14240 }
14241
14242 return true;
14243}
14244
14245bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
14246 // Get the operand value into 'Result'.
14247 if (!Visit(E->getSubExpr()))
14248 return false;
14249
14250 switch (E->getOpcode()) {
14251 default:
14252 return Error(E);
14253 case UO_Extension:
14254 return true;
14255 case UO_Plus:
14256 // The result is always just the subexpr.
14257 return true;
14258 case UO_Minus:
14259 if (Result.isComplexFloat()) {
14260 Result.getComplexFloatReal().changeSign();
14261 Result.getComplexFloatImag().changeSign();
14262 }
14263 else {
14264 Result.getComplexIntReal() = -Result.getComplexIntReal();
14265 Result.getComplexIntImag() = -Result.getComplexIntImag();
14266 }
14267 return true;
14268 case UO_Not:
14269 if (Result.isComplexFloat())
14270 Result.getComplexFloatImag().changeSign();
14271 else
14272 Result.getComplexIntImag() = -Result.getComplexIntImag();
14273 return true;
14274 }
14275}
14276
14277bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
14278 if (E->getNumInits() == 2) {
14279 if (E->getType()->isComplexType()) {
14280 Result.makeComplexFloat();
14281 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info))
14282 return false;
14283 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info))
14284 return false;
14285 } else {
14286 Result.makeComplexInt();
14287 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info))
14288 return false;
14289 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info))
14290 return false;
14291 }
14292 return true;
14293 }
14294 return ExprEvaluatorBaseTy::VisitInitListExpr(E);
14295}
14296
14297bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) {
14298 switch (E->getBuiltinCallee()) {
14299 case Builtin::BI__builtin_complex:
14300 Result.makeComplexFloat();
14301 if (!EvaluateFloat(E->getArg(0), Result.FloatReal, Info))
14302 return false;
14303 if (!EvaluateFloat(E->getArg(1), Result.FloatImag, Info))
14304 return false;
14305 return true;
14306
14307 default:
14308 break;
14309 }
14310
14311 return ExprEvaluatorBaseTy::VisitCallExpr(E);
14312}
14313
14314//===----------------------------------------------------------------------===//
14315// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic
14316// implicit conversion.
14317//===----------------------------------------------------------------------===//
14318
14319namespace {
14320class AtomicExprEvaluator :
14321 public ExprEvaluatorBase<AtomicExprEvaluator> {
14322 const LValue *This;
14323 APValue &Result;
14324public:
14325 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
14326 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
14327
14328 bool Success(const APValue &V, const Expr *E) {
14329 Result = V;
14330 return true;
14331 }
14332
14333 bool ZeroInitialization(const Expr *E) {
14334 ImplicitValueInitExpr VIE(
14335 E->getType()->castAs<AtomicType>()->getValueType());
14336 // For atomic-qualified class (and array) types in C++, initialize the
14337 // _Atomic-wrapped subobject directly, in-place.
14338 return This ? EvaluateInPlace(Result, Info, *This, &VIE)
14339 : Evaluate(Result, Info, &VIE);
14340 }
14341
14342 bool VisitCastExpr(const CastExpr *E) {
14343 switch (E->getCastKind()) {
14344 default:
14345 return ExprEvaluatorBaseTy::VisitCastExpr(E);
14346 case CK_NonAtomicToAtomic:
14347 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
14348 : Evaluate(Result, Info, E->getSubExpr());
14349 }
14350 }
14351};
14352} // end anonymous namespace
14353
14354static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
14355 EvalInfo &Info) {
14356 assert(!E->isValueDependent());
14357 assert(E->isRValue() && E->getType()->isAtomicType());
14358 return AtomicExprEvaluator(Info, This, Result).Visit(E);
14359}
14360
14361//===----------------------------------------------------------------------===//
14362// Void expression evaluation, primarily for a cast to void on the LHS of a
14363// comma operator
14364//===----------------------------------------------------------------------===//
14365
14366namespace {
14367class VoidExprEvaluator
14368 : public ExprEvaluatorBase<VoidExprEvaluator> {
14369public:
14370 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {}
14371
14372 bool Success(const APValue &V, const Expr *e) { return true; }
14373
14374 bool ZeroInitialization(const Expr *E) { return true; }
14375
14376 bool VisitCastExpr(const CastExpr *E) {
14377 switch (E->getCastKind()) {
14378 default:
14379 return ExprEvaluatorBaseTy::VisitCastExpr(E);
14380 case CK_ToVoid:
14381 VisitIgnoredValue(E->getSubExpr());
14382 return true;
14383 }
14384 }
14385
14386 bool VisitCallExpr(const CallExpr *E) {
14387 switch (E->getBuiltinCallee()) {
14388 case Builtin::BI__assume:
14389 case Builtin::BI__builtin_assume:
14390 // The argument is not evaluated!
14391 return true;
14392
14393 case Builtin::BI__builtin_operator_delete:
14394 return HandleOperatorDeleteCall(Info, E);
14395
14396 default:
14397 break;
14398 }
14399
14400 return ExprEvaluatorBaseTy::VisitCallExpr(E);
14401 }
14402
14403 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E);
14404};
14405} // end anonymous namespace
14406
14407bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) {
14408 // We cannot speculatively evaluate a delete expression.
14409 if (Info.SpeculativeEvaluationDepth)
14410 return false;
14411
14412 FunctionDecl *OperatorDelete = E->getOperatorDelete();
14413 if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) {
14414 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
14415 << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete;
14416 return false;
14417 }
14418
14419 const Expr *Arg = E->getArgument();
14420
14421 LValue Pointer;
14422 if (!EvaluatePointer(Arg, Pointer, Info))
14423 return false;
14424 if (Pointer.Designator.Invalid)
14425 return false;
14426
14427 // Deleting a null pointer has no effect.
14428 if (Pointer.isNullPointer()) {
14429 // This is the only case where we need to produce an extension warning:
14430 // the only other way we can succeed is if we find a dynamic allocation,
14431 // and we will have warned when we allocated it in that case.
14432 if (!Info.getLangOpts().CPlusPlus20)
14433 Info.CCEDiag(E, diag::note_constexpr_new);
14434 return true;
14435 }
14436
14437 Optional<DynAlloc *> Alloc = CheckDeleteKind(
14438 Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New);
14439 if (!Alloc)
14440 return false;
14441 QualType AllocType = Pointer.Base.getDynamicAllocType();
14442
14443 // For the non-array case, the designator must be empty if the static type
14444 // does not have a virtual destructor.
14445 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 &&
14446 !hasVirtualDestructor(Arg->getType()->getPointeeType())) {
14447 Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor)
14448 << Arg->getType()->getPointeeType() << AllocType;
14449 return false;
14450 }
14451
14452 // For a class type with a virtual destructor, the selected operator delete
14453 // is the one looked up when building the destructor.
14454 if (!E->isArrayForm() && !E->isGlobalDelete()) {
14455 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType);
14456 if (VirtualDelete &&
14457 !VirtualDelete->isReplaceableGlobalAllocationFunction()) {
14458 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable)
14459 << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete;
14460 return false;
14461 }
14462 }
14463
14464 if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(),
14465 (*Alloc)->Value, AllocType))
14466 return false;
14467
14468 if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) {
14469 // The element was already erased. This means the destructor call also
14470 // deleted the object.
14471 // FIXME: This probably results in undefined behavior before we get this
14472 // far, and should be diagnosed elsewhere first.
14473 Info.FFDiag(E, diag::note_constexpr_double_delete);
14474 return false;
14475 }
14476
14477 return true;
14478}
14479
14480static bool EvaluateVoid(const Expr *E, EvalInfo &Info) {
14481 assert(!E->isValueDependent());
14482 assert(E->isRValue() && E->getType()->isVoidType());
14483 return VoidExprEvaluator(Info).Visit(E);
14484}
14485
14486//===----------------------------------------------------------------------===//
14487// Top level Expr::EvaluateAsRValue method.
14488//===----------------------------------------------------------------------===//
14489
14490static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
14491 assert(!E->isValueDependent());
14492 // In C, function designators are not lvalues, but we evaluate them as if they
14493 // are.
14494 QualType T = E->getType();
14495 if (E->isGLValue() || T->isFunctionType()) {
14496 LValue LV;
14497 if (!EvaluateLValue(E, LV, Info))
14498 return false;
14499 LV.moveInto(Result);
14500 } else if (T->isVectorType()) {
14501 if (!EvaluateVector(E, Result, Info))
14502 return false;
14503 } else if (T->isIntegralOrEnumerationType()) {
14504 if (!IntExprEvaluator(Info, Result).Visit(E))
14505 return false;
14506 } else if (T->hasPointerRepresentation()) {
14507 LValue LV;
14508 if (!EvaluatePointer(E, LV, Info))
14509 return false;
14510 LV.moveInto(Result);
14511 } else if (T->isRealFloatingType()) {
14512 llvm::APFloat F(0.0);
14513 if (!EvaluateFloat(E, F, Info))
14514 return false;
14515 Result = APValue(F);
14516 } else if (T->isAnyComplexType()) {
14517 ComplexValue C;
14518 if (!EvaluateComplex(E, C, Info))
14519 return false;
14520 C.moveInto(Result);
14521 } else if (T->isFixedPointType()) {
14522 if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false;
14523 } else if (T->isMemberPointerType()) {
14524 MemberPtr P;
14525 if (!EvaluateMemberPointer(E, P, Info))
14526 return false;
14527 P.moveInto(Result);
14528 return true;
14529 } else if (T->isArrayType()) {
14530 LValue LV;
14531 APValue &Value =
14532 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
14533 if (!EvaluateArray(E, LV, Value, Info))
14534 return false;
14535 Result = Value;
14536 } else if (T->isRecordType()) {
14537 LValue LV;
14538 APValue &Value =
14539 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV);
14540 if (!EvaluateRecord(E, LV, Value, Info))
14541 return false;
14542 Result = Value;
14543 } else if (T->isVoidType()) {
14544 if (!Info.getLangOpts().CPlusPlus11)
14545 Info.CCEDiag(E, diag::note_constexpr_nonliteral)
14546 << E->getType();
14547 if (!EvaluateVoid(E, Info))
14548 return false;
14549 } else if (T->isAtomicType()) {
14550 QualType Unqual = T.getAtomicUnqualifiedType();
14551 if (Unqual->isArrayType() || Unqual->isRecordType()) {
14552 LValue LV;
14553 APValue &Value = Info.CurrentCall->createTemporary(
14554 E, Unqual, ScopeKind::FullExpression, LV);
14555 if (!EvaluateAtomic(E, &LV, Value, Info))
14556 return false;
14557 } else {
14558 if (!EvaluateAtomic(E, nullptr, Result, Info))
14559 return false;
14560 }
14561 } else if (Info.getLangOpts().CPlusPlus11) {
14562 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
14563 return false;
14564 } else {
14565 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr);
14566 return false;
14567 }
14568
14569 return true;
14570}
14571
14572/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some
14573/// cases, the in-place evaluation is essential, since later initializers for
14574/// an object can indirectly refer to subobjects which were initialized earlier.
14575static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
14576 const Expr *E, bool AllowNonLiteralTypes) {
14577 assert(!E->isValueDependent());
14578
14579 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This))
14580 return false;
14581
14582 if (E->isRValue()) {
14583 // Evaluate arrays and record types in-place, so that later initializers can
14584 // refer to earlier-initialized members of the object.
14585 QualType T = E->getType();
14586 if (T->isArrayType())
14587 return EvaluateArray(E, This, Result, Info);
14588 else if (T->isRecordType())
14589 return EvaluateRecord(E, This, Result, Info);
14590 else if (T->isAtomicType()) {
14591 QualType Unqual = T.getAtomicUnqualifiedType();
14592 if (Unqual->isArrayType() || Unqual->isRecordType())
14593 return EvaluateAtomic(E, &This, Result, Info);
14594 }
14595 }
14596
14597 // For any other type, in-place evaluation is unimportant.
14598 return Evaluate(Result, Info, E);
14599}
14600
14601/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit
14602/// lvalue-to-rvalue cast if it is an lvalue.
14603static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) {
14604 assert(!E->isValueDependent());
14605 if (Info.EnableNewConstInterp) {
14606 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result))
14607 return false;
14608 } else {
14609 if (E->getType().isNull())
14610 return false;
14611
14612 if (!CheckLiteralType(Info, E))
14613 return false;
14614
14615 if (!::Evaluate(Result, Info, E))
14616 return false;
14617
14618 if (E->isGLValue()) {
14619 LValue LV;
14620 LV.setFrom(Info.Ctx, Result);
14621 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result))
14622 return false;
14623 }
14624 }
14625
14626 // Check this core constant expression is a constant expression.
14627 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result,
14628 ConstantExprKind::Normal) &&
14629 CheckMemoryLeaks(Info);
14630}
14631
14632static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result,
14633 const ASTContext &Ctx, bool &IsConst) {
14634 // Fast-path evaluations of integer literals, since we sometimes see files
14635 // containing vast quantities of these.
14636 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) {
14637 Result.Val = APValue(APSInt(L->getValue(),
14638 L->getType()->isUnsignedIntegerType()));
14639 IsConst = true;
14640 return true;
14641 }
14642
14643 // This case should be rare, but we need to check it before we check on
14644 // the type below.
14645 if (Exp->getType().isNull()) {
14646 IsConst = false;
14647 return true;
14648 }
14649
14650 // FIXME: Evaluating values of large array and record types can cause
14651 // performance problems. Only do so in C++11 for now.
14652 if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
14653 Exp->getType()->isRecordType()) &&
14654 !Ctx.getLangOpts().CPlusPlus11) {
14655 IsConst = false;
14656 return true;
14657 }
14658 return false;
14659}
14660
14661static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result,
14662 Expr::SideEffectsKind SEK) {
14663 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) ||
14664 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior);
14665}
14666
14667static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result,
14668 const ASTContext &Ctx, EvalInfo &Info) {
14669 assert(!E->isValueDependent());
14670 bool IsConst;
14671 if (FastEvaluateAsRValue(E, Result, Ctx, IsConst))
14672 return IsConst;
14673
14674 return EvaluateAsRValue(Info, E, Result.Val);
14675}
14676
14677static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult,
14678 const ASTContext &Ctx,
14679 Expr::SideEffectsKind AllowSideEffects,
14680 EvalInfo &Info) {
14681 assert(!E->isValueDependent());
14682 if (!E->getType()->isIntegralOrEnumerationType())
14683 return false;
14684
14685 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) ||
14686 !ExprResult.Val.isInt() ||
14687 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14688 return false;
14689
14690 return true;
14691}
14692
14693static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult,
14694 const ASTContext &Ctx,
14695 Expr::SideEffectsKind AllowSideEffects,
14696 EvalInfo &Info) {
14697 assert(!E->isValueDependent());
14698 if (!E->getType()->isFixedPointType())
14699 return false;
14700
14701 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info))
14702 return false;
14703
14704 if (!ExprResult.Val.isFixedPoint() ||
14705 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14706 return false;
14707
14708 return true;
14709}
14710
14711/// EvaluateAsRValue - Return true if this is a constant which we can fold using
14712/// any crazy technique (that has nothing to do with language standards) that
14713/// we want to. If this function returns true, it returns the folded constant
14714/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion
14715/// will be applied to the result.
14716bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
14717 bool InConstantContext) const {
14718 assert(!isValueDependent() &&
14719 "Expression evaluator can't be called on a dependent expression.");
14720 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14721 Info.InConstantContext = InConstantContext;
14722 return ::EvaluateAsRValue(this, Result, Ctx, Info);
14723}
14724
14725bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
14726 bool InConstantContext) const {
14727 assert(!isValueDependent() &&
14728 "Expression evaluator can't be called on a dependent expression.");
14729 EvalResult Scratch;
14730 return EvaluateAsRValue(Scratch, Ctx, InConstantContext) &&
14731 HandleConversionToBool(Scratch.Val, Result);
14732}
14733
14734bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
14735 SideEffectsKind AllowSideEffects,
14736 bool InConstantContext) const {
14737 assert(!isValueDependent() &&
14738 "Expression evaluator can't be called on a dependent expression.");
14739 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14740 Info.InConstantContext = InConstantContext;
14741 return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info);
14742}
14743
14744bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
14745 SideEffectsKind AllowSideEffects,
14746 bool InConstantContext) const {
14747 assert(!isValueDependent() &&
14748 "Expression evaluator can't be called on a dependent expression.");
14749 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
14750 Info.InConstantContext = InConstantContext;
14751 return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info);
14752}
14753
14754bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx,
14755 SideEffectsKind AllowSideEffects,
14756 bool InConstantContext) const {
14757 assert(!isValueDependent() &&
14758 "Expression evaluator can't be called on a dependent expression.");
14759
14760 if (!getType()->isRealFloatingType())
14761 return false;
14762
14763 EvalResult ExprResult;
14764 if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) ||
14765 !ExprResult.Val.isFloat() ||
14766 hasUnacceptableSideEffect(ExprResult, AllowSideEffects))
14767 return false;
14768
14769 Result = ExprResult.Val.getFloat();
14770 return true;
14771}
14772
14773bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
14774 bool InConstantContext) const {
14775 assert(!isValueDependent() &&
14776 "Expression evaluator can't be called on a dependent expression.");
14777
14778 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold);
14779 Info.InConstantContext = InConstantContext;
14780 LValue LV;
14781 CheckedTemporaries CheckedTemps;
14782 if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() ||
14783 Result.HasSideEffects ||
14784 !CheckLValueConstantExpression(Info, getExprLoc(),
14785 Ctx.getLValueReferenceType(getType()), LV,
14786 ConstantExprKind::Normal, CheckedTemps))
14787 return false;
14788
14789 LV.moveInto(Result.Val);
14790 return true;
14791}
14792
14793static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base,
14794 APValue DestroyedValue, QualType Type,
14795 SourceLocation Loc, Expr::EvalStatus &EStatus,
14796 bool IsConstantDestruction) {
14797 EvalInfo Info(Ctx, EStatus,
14798 IsConstantDestruction ? EvalInfo::EM_ConstantExpression
14799 : EvalInfo::EM_ConstantFold);
14800 Info.setEvaluatingDecl(Base, DestroyedValue,
14801 EvalInfo::EvaluatingDeclKind::Dtor);
14802 Info.InConstantContext = IsConstantDestruction;
14803
14804 LValue LVal;
14805 LVal.set(Base);
14806
14807 if (!HandleDestruction(Info, Loc, Base, DestroyedValue, Type) ||
14808 EStatus.HasSideEffects)
14809 return false;
14810
14811 if (!Info.discardCleanups())
14812 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14813
14814 return true;
14815}
14816
14817bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx,
14818 ConstantExprKind Kind) const {
14819 assert(!isValueDependent() &&
14820 "Expression evaluator can't be called on a dependent expression.");
14821
14822 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression;
14823 EvalInfo Info(Ctx, Result, EM);
14824 Info.InConstantContext = true;
14825
14826 // The type of the object we're initializing is 'const T' for a class NTTP.
14827 QualType T = getType();
14828 if (Kind == ConstantExprKind::ClassTemplateArgument)
14829 T.addConst();
14830
14831 // If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to
14832 // represent the result of the evaluation. CheckConstantExpression ensures
14833 // this doesn't escape.
14834 MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true);
14835 APValue::LValueBase Base(&BaseMTE);
14836
14837 Info.setEvaluatingDecl(Base, Result.Val);
14838 LValue LVal;
14839 LVal.set(Base);
14840
14841 if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || Result.HasSideEffects)
14842 return false;
14843
14844 if (!Info.discardCleanups())
14845 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14846
14847 if (!CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this),
14848 Result.Val, Kind))
14849 return false;
14850 if (!CheckMemoryLeaks(Info))
14851 return false;
14852
14853 // If this is a class template argument, it's required to have constant
14854 // destruction too.
14855 if (Kind == ConstantExprKind::ClassTemplateArgument &&
14856 (!EvaluateDestruction(Ctx, Base, Result.Val, T, getBeginLoc(), Result,
14857 true) ||
14858 Result.HasSideEffects)) {
14859 // FIXME: Prefix a note to indicate that the problem is lack of constant
14860 // destruction.
14861 return false;
14862 }
14863
14864 return true;
14865}
14866
14867bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,
14868 const VarDecl *VD,
14869 SmallVectorImpl<PartialDiagnosticAt> &Notes,
14870 bool IsConstantInitialization) const {
14871 assert(!isValueDependent() &&
14872 "Expression evaluator can't be called on a dependent expression.");
14873
14874 // FIXME: Evaluating initializers for large array and record types can cause
14875 // performance problems. Only do so in C++11 for now.
14876 if (isRValue() && (getType()->isArrayType() || getType()->isRecordType()) &&
14877 !Ctx.getLangOpts().CPlusPlus11)
14878 return false;
14879
14880 Expr::EvalStatus EStatus;
14881 EStatus.Diag = &Notes;
14882
14883 EvalInfo Info(Ctx, EStatus,
14884 (IsConstantInitialization && Ctx.getLangOpts().CPlusPlus11)
14885 ? EvalInfo::EM_ConstantExpression
14886 : EvalInfo::EM_ConstantFold);
14887 Info.setEvaluatingDecl(VD, Value);
14888 Info.InConstantContext = IsConstantInitialization;
14889
14890 SourceLocation DeclLoc = VD->getLocation();
14891 QualType DeclTy = VD->getType();
14892
14893 if (Info.EnableNewConstInterp) {
14894 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
14895 if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
14896 return false;
14897 } else {
14898 LValue LVal;
14899 LVal.set(VD);
14900
14901 if (!EvaluateInPlace(Value, Info, LVal, this,
14902 /*AllowNonLiteralTypes=*/true) ||
14903 EStatus.HasSideEffects)
14904 return false;
14905
14906 // At this point, any lifetime-extended temporaries are completely
14907 // initialized.
14908 Info.performLifetimeExtension();
14909
14910 if (!Info.discardCleanups())
14911 llvm_unreachable("Unhandled cleanup; missing full expression marker?");
14912 }
14913 return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
14914 ConstantExprKind::Normal) &&
14915 CheckMemoryLeaks(Info);
14916}
14917
14918bool VarDecl::evaluateDestruction(
14919 SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
14920 Expr::EvalStatus EStatus;
14921 EStatus.Diag = &Notes;
14922
14923 // Only treat the destruction as constant destruction if we formally have
14924 // constant initialization (or are usable in a constant expression).
14925 bool IsConstantDestruction = hasConstantInitialization();
14926
14927 // Make a copy of the value for the destructor to mutate, if we know it.
14928 // Otherwise, treat the value as default-initialized; if the destructor works
14929 // anyway, then the destruction is constant (and must be essentially empty).
14930 APValue DestroyedValue;
14931 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent())
14932 DestroyedValue = *getEvaluatedValue();
14933 else if (!getDefaultInitValue(getType(), DestroyedValue))
14934 return false;
14935
14936 if (!EvaluateDestruction(getASTContext(), this, std::move(DestroyedValue),
14937 getType(), getLocation(), EStatus,
14938 IsConstantDestruction) ||
14939 EStatus.HasSideEffects)
14940 return false;
14941
14942 ensureEvaluatedStmt()->HasConstantDestruction = true;
14943 return true;
14944}
14945
14946/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
14947/// constant folded, but discard the result.
14948bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const {
14949 assert(!isValueDependent() &&
14950 "Expression evaluator can't be called on a dependent expression.");
14951
14952 EvalResult Result;
14953 return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) &&
14954 !hasUnacceptableSideEffect(Result, SEK);
14955}
14956
14957APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
14958 SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
14959 assert(!isValueDependent() &&
14960 "Expression evaluator can't be called on a dependent expression.");
14961
14962 EvalResult EVResult;
14963 EVResult.Diag = Diag;
14964 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14965 Info.InConstantContext = true;
14966
14967 bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info);
14968 (void)Result;
14969 assert(Result && "Could not evaluate expression");
14970 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
14971
14972 return EVResult.Val.getInt();
14973}
14974
14975APSInt Expr::EvaluateKnownConstIntCheckOverflow(
14976 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
14977 assert(!isValueDependent() &&
14978 "Expression evaluator can't be called on a dependent expression.");
14979
14980 EvalResult EVResult;
14981 EVResult.Diag = Diag;
14982 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
14983 Info.InConstantContext = true;
14984 Info.CheckingForUndefinedBehavior = true;
14985
14986 bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val);
14987 (void)Result;
14988 assert(Result && "Could not evaluate expression");
14989 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer");
14990
14991 return EVResult.Val.getInt();
14992}
14993
14994void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
14995 assert(!isValueDependent() &&
14996 "Expression evaluator can't be called on a dependent expression.");
14997
14998 bool IsConst;
14999 EvalResult EVResult;
15000 if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) {
15001 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects);
15002 Info.CheckingForUndefinedBehavior = true;
15003 (void)::EvaluateAsRValue(Info, this, EVResult.Val);
15004 }
15005}
15006
15007bool Expr::EvalResult::isGlobalLValue() const {
15008 assert(Val.isLValue());
15009 return IsGlobalLValue(Val.getLValueBase());
15010}
15011
15012/// isIntegerConstantExpr - this recursive routine will test if an expression is
15013/// an integer constant expression.
15014
15015/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero,
15016/// comma, etc
15017
15018// CheckICE - This function does the fundamental ICE checking: the returned
15019// ICEDiag contains an ICEKind indicating whether the expression is an ICE,
15020// and a (possibly null) SourceLocation indicating the location of the problem.
15021//
15022// Note that to reduce code duplication, this helper does no evaluation
15023// itself; the caller checks whether the expression is evaluatable, and
15024// in the rare cases where CheckICE actually cares about the evaluated
15025// value, it calls into Evaluate.
15026
15027namespace {
15028
15029enum ICEKind {
15030 /// This expression is an ICE.
15031 IK_ICE,
15032 /// This expression is not an ICE, but if it isn't evaluated, it's
15033 /// a legal subexpression for an ICE. This return value is used to handle
15034 /// the comma operator in C99 mode, and non-constant subexpressions.
15035 IK_ICEIfUnevaluated,
15036 /// This expression is not an ICE, and is not a legal subexpression for one.
15037 IK_NotICE
15038};
15039
15040struct ICEDiag {
15041 ICEKind Kind;
15042 SourceLocation Loc;
15043
15044 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {}
15045};
15046
15047}
15048
15049static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); }
15050
15051static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; }
15052
15053static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) {
15054 Expr::EvalResult EVResult;
15055 Expr::EvalStatus Status;
15056 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
15057
15058 Info.InConstantContext = true;
15059 if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects ||
15060 !EVResult.Val.isInt())
15061 return ICEDiag(IK_NotICE, E->getBeginLoc());
15062
15063 return NoDiag();
15064}
15065
15066static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
15067 assert(!E->isValueDependent() && "Should not see value dependent exprs!");
15068 if (!E->getType()->isIntegralOrEnumerationType())
15069 return ICEDiag(IK_NotICE, E->getBeginLoc());
15070
15071 switch (E->getStmtClass()) {
15072#define ABSTRACT_STMT(Node)
15073#define STMT(Node, Base) case Expr::Node##Class:
15074#define EXPR(Node, Base)
15075#include "clang/AST/StmtNodes.inc"
15076 case Expr::PredefinedExprClass:
15077 case Expr::FloatingLiteralClass:
15078 case Expr::ImaginaryLiteralClass:
15079 case Expr::StringLiteralClass:
15080 case Expr::ArraySubscriptExprClass:
15081 case Expr::MatrixSubscriptExprClass:
15082 case Expr::OMPArraySectionExprClass:
15083 case Expr::OMPArrayShapingExprClass:
15084 case Expr::OMPIteratorExprClass:
15085 case Expr::MemberExprClass:
15086 case Expr::CompoundAssignOperatorClass:
15087 case Expr::CompoundLiteralExprClass:
15088 case Expr::ExtVectorElementExprClass:
15089 case Expr::DesignatedInitExprClass:
15090 case Expr::ArrayInitLoopExprClass:
15091 case Expr::ArrayInitIndexExprClass:
15092 case Expr::NoInitExprClass:
15093 case Expr::DesignatedInitUpdateExprClass:
15094 case Expr::ImplicitValueInitExprClass:
15095 case Expr::ParenListExprClass:
15096 case Expr::VAArgExprClass:
15097 case Expr::AddrLabelExprClass:
15098 case Expr::StmtExprClass:
15099 case Expr::CXXMemberCallExprClass:
15100 case Expr::CUDAKernelCallExprClass:
15101 case Expr::CXXAddrspaceCastExprClass:
15102 case Expr::CXXDynamicCastExprClass:
15103 case Expr::CXXTypeidExprClass:
15104 case Expr::CXXUuidofExprClass:
15105 case Expr::MSPropertyRefExprClass:
15106 case Expr::MSPropertySubscriptExprClass:
15107 case Expr::CXXNullPtrLiteralExprClass:
15108 case Expr::UserDefinedLiteralClass:
15109 case Expr::CXXThisExprClass:
15110 case Expr::CXXThrowExprClass:
15111 case Expr::CXXNewExprClass:
15112 case Expr::CXXDeleteExprClass:
15113 case Expr::CXXPseudoDestructorExprClass:
15114 case Expr::UnresolvedLookupExprClass:
15115 case Expr::TypoExprClass:
15116 case Expr::RecoveryExprClass:
15117 case Expr::DependentScopeDeclRefExprClass:
15118 case Expr::CXXConstructExprClass:
15119 case Expr::CXXInheritedCtorInitExprClass:
15120 case Expr::CXXStdInitializerListExprClass:
15121 case Expr::CXXBindTemporaryExprClass:
15122 case Expr::ExprWithCleanupsClass:
15123 case Expr::CXXTemporaryObjectExprClass:
15124 case Expr::CXXUnresolvedConstructExprClass:
15125 case Expr::CXXDependentScopeMemberExprClass:
15126 case Expr::UnresolvedMemberExprClass:
15127 case Expr::ObjCStringLiteralClass:
15128 case Expr::ObjCBoxedExprClass:
15129 case Expr::ObjCArrayLiteralClass:
15130 case Expr::ObjCDictionaryLiteralClass:
15131 case Expr::ObjCEncodeExprClass:
15132 case Expr::ObjCMessageExprClass:
15133 case Expr::ObjCSelectorExprClass:
15134 case Expr::ObjCProtocolExprClass:
15135 case Expr::ObjCIvarRefExprClass:
15136 case Expr::ObjCPropertyRefExprClass:
15137 case Expr::ObjCSubscriptRefExprClass:
15138 case Expr::ObjCIsaExprClass:
15139 case Expr::ObjCAvailabilityCheckExprClass:
15140 case Expr::ShuffleVectorExprClass:
15141 case Expr::ConvertVectorExprClass:
15142 case Expr::BlockExprClass:
15143 case Expr::NoStmtClass:
15144 case Expr::OpaqueValueExprClass:
15145 case Expr::PackExpansionExprClass:
15146 case Expr::SubstNonTypeTemplateParmPackExprClass:
15147 case Expr::FunctionParmPackExprClass:
15148 case Expr::AsTypeExprClass:
15149 case Expr::ObjCIndirectCopyRestoreExprClass:
15150 case Expr::MaterializeTemporaryExprClass:
15151 case Expr::PseudoObjectExprClass:
15152 case Expr::AtomicExprClass:
15153 case Expr::LambdaExprClass:
15154 case Expr::CXXFoldExprClass:
15155 case Expr::CoawaitExprClass:
15156 case Expr::DependentCoawaitExprClass:
15157 case Expr::CoyieldExprClass:
15158 return ICEDiag(IK_NotICE, E->getBeginLoc());
15159
15160 case Expr::InitListExprClass: {
15161 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the
15162 // form "T x = { a };" is equivalent to "T x = a;".
15163 // Unless we're initializing a reference, T is a scalar as it is known to be
15164 // of integral or enumeration type.
15165 if (E->isRValue())
15166 if (cast<InitListExpr>(E)->getNumInits() == 1)
15167 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx);
15168 return ICEDiag(IK_NotICE, E->getBeginLoc());
15169 }
15170
15171 case Expr::SizeOfPackExprClass:
15172 case Expr::GNUNullExprClass:
15173 case Expr::SourceLocExprClass:
15174 return NoDiag();
15175
15176 case Expr::SubstNonTypeTemplateParmExprClass:
15177 return
15178 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx);
15179
15180 case Expr::ConstantExprClass:
15181 return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx);
15182
15183 case Expr::ParenExprClass:
15184 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx);
15185 case Expr::GenericSelectionExprClass:
15186 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx);
15187 case Expr::IntegerLiteralClass:
15188 case Expr::FixedPointLiteralClass:
15189 case Expr::CharacterLiteralClass:
15190 case Expr::ObjCBoolLiteralExprClass:
15191 case Expr::CXXBoolLiteralExprClass:
15192 case Expr::CXXScalarValueInitExprClass:
15193 case Expr::TypeTraitExprClass:
15194 case Expr::ConceptSpecializationExprClass:
15195 case Expr::RequiresExprClass:
15196 case Expr::ArrayTypeTraitExprClass:
15197 case Expr::ExpressionTraitExprClass:
15198 case Expr::CXXNoexceptExprClass:
15199 return NoDiag();
15200 case Expr::CallExprClass:
15201 case Expr::CXXOperatorCallExprClass: {
15202 // C99 6.6/3 allows function calls within unevaluated subexpressions of
15203 // constant expressions, but they can never be ICEs because an ICE cannot
15204 // contain an operand of (pointer to) function type.
15205 const CallExpr *CE = cast<CallExpr>(E);
15206 if (CE->getBuiltinCallee())
15207 return CheckEvalInICE(E, Ctx);
15208 return ICEDiag(IK_NotICE, E->getBeginLoc());
15209 }
15210 case Expr::CXXRewrittenBinaryOperatorClass:
15211 return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(),
15212 Ctx);
15213 case Expr::DeclRefExprClass: {
15214 const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl();
15215 if (isa<EnumConstantDecl>(D))
15216 return NoDiag();
15217
15218 // C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified
15219 // integer variables in constant expressions:
15220 //
15221 // C++ 7.1.5.1p2
15222 // A variable of non-volatile const-qualified integral or enumeration
15223 // type initialized by an ICE can be used in ICEs.
15224 //
15225 // We sometimes use CheckICE to check the C++98 rules in C++11 mode. In
15226 // that mode, use of reference variables should not be allowed.
15227 const VarDecl *VD = dyn_cast<VarDecl>(D);
15228 if (VD && VD->isUsableInConstantExpressions(Ctx) &&
15229 !VD->getType()->isReferenceType())
15230 return NoDiag();
15231
15232 return ICEDiag(IK_NotICE, E->getBeginLoc());
15233 }
15234 case Expr::UnaryOperatorClass: {
15235 const UnaryOperator *Exp = cast<UnaryOperator>(E);
15236 switch (Exp->getOpcode()) {
15237 case UO_PostInc:
15238 case UO_PostDec:
15239 case UO_PreInc:
15240 case UO_PreDec:
15241 case UO_AddrOf:
15242 case UO_Deref:
15243 case UO_Coawait:
15244 // C99 6.6/3 allows increment and decrement within unevaluated
15245 // subexpressions of constant expressions, but they can never be ICEs
15246 // because an ICE cannot contain an lvalue operand.
15247 return ICEDiag(IK_NotICE, E->getBeginLoc());
15248 case UO_Extension:
15249 case UO_LNot:
15250 case UO_Plus:
15251 case UO_Minus:
15252 case UO_Not:
15253 case UO_Real:
15254 case UO_Imag:
15255 return CheckICE(Exp->getSubExpr(), Ctx);
15256 }
15257 llvm_unreachable("invalid unary operator class");
15258 }
15259 case Expr::OffsetOfExprClass: {
15260 // Note that per C99, offsetof must be an ICE. And AFAIK, using
15261 // EvaluateAsRValue matches the proposed gcc behavior for cases like
15262 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect
15263 // compliance: we should warn earlier for offsetof expressions with
15264 // array subscripts that aren't ICEs, and if the array subscripts
15265 // are ICEs, the value of the offsetof must be an integer constant.
15266 return CheckEvalInICE(E, Ctx);
15267 }
15268 case Expr::UnaryExprOrTypeTraitExprClass: {
15269 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
15270 if ((Exp->getKind() == UETT_SizeOf) &&
15271 Exp->getTypeOfArgument()->isVariableArrayType())
15272 return ICEDiag(IK_NotICE, E->getBeginLoc());
15273 return NoDiag();
15274 }
15275 case Expr::BinaryOperatorClass: {
15276 const BinaryOperator *Exp = cast<BinaryOperator>(E);
15277 switch (Exp->getOpcode()) {
15278 case BO_PtrMemD:
15279 case BO_PtrMemI:
15280 case BO_Assign:
15281 case BO_MulAssign:
15282 case BO_DivAssign:
15283 case BO_RemAssign:
15284 case BO_AddAssign:
15285 case BO_SubAssign:
15286 case BO_ShlAssign:
15287 case BO_ShrAssign:
15288 case BO_AndAssign:
15289 case BO_XorAssign:
15290 case BO_OrAssign:
15291 // C99 6.6/3 allows assignments within unevaluated subexpressions of
15292 // constant expressions, but they can never be ICEs because an ICE cannot
15293 // contain an lvalue operand.
15294 return ICEDiag(IK_NotICE, E->getBeginLoc());
15295
15296 case BO_Mul:
15297 case BO_Div:
15298 case BO_Rem:
15299 case BO_Add:
15300 case BO_Sub:
15301 case BO_Shl:
15302 case BO_Shr:
15303 case BO_LT:
15304 case BO_GT:
15305 case BO_LE:
15306 case BO_GE:
15307 case BO_EQ:
15308 case BO_NE:
15309 case BO_And:
15310 case BO_Xor:
15311 case BO_Or:
15312 case BO_Comma:
15313 case BO_Cmp: {
15314 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
15315 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
15316 if (Exp->getOpcode() == BO_Div ||
15317 Exp->getOpcode() == BO_Rem) {
15318 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure
15319 // we don't evaluate one.
15320 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) {
15321 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx);
15322 if (REval == 0)
15323 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15324 if (REval.isSigned() && REval.isAllOnesValue()) {
15325 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx);
15326 if (LEval.isMinSignedValue())
15327 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15328 }
15329 }
15330 }
15331 if (Exp->getOpcode() == BO_Comma) {
15332 if (Ctx.getLangOpts().C99) {
15333 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE
15334 // if it isn't evaluated.
15335 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE)
15336 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc());
15337 } else {
15338 // In both C89 and C++, commas in ICEs are illegal.
15339 return ICEDiag(IK_NotICE, E->getBeginLoc());
15340 }
15341 }
15342 return Worst(LHSResult, RHSResult);
15343 }
15344 case BO_LAnd:
15345 case BO_LOr: {
15346 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx);
15347 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx);
15348 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) {
15349 // Rare case where the RHS has a comma "side-effect"; we need
15350 // to actually check the condition to see whether the side
15351 // with the comma is evaluated.
15352 if ((Exp->getOpcode() == BO_LAnd) !=
15353 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0))
15354 return RHSResult;
15355 return NoDiag();
15356 }
15357
15358 return Worst(LHSResult, RHSResult);
15359 }
15360 }
15361 llvm_unreachable("invalid binary operator kind");
15362 }
15363 case Expr::ImplicitCastExprClass:
15364 case Expr::CStyleCastExprClass:
15365 case Expr::CXXFunctionalCastExprClass:
15366 case Expr::CXXStaticCastExprClass:
15367 case Expr::CXXReinterpretCastExprClass:
15368 case Expr::CXXConstCastExprClass:
15369 case Expr::ObjCBridgedCastExprClass: {
15370 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr();
15371 if (isa<ExplicitCastExpr>(E)) {
15372 if (const FloatingLiteral *FL
15373 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) {
15374 unsigned DestWidth = Ctx.getIntWidth(E->getType());
15375 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType();
15376 APSInt IgnoredVal(DestWidth, !DestSigned);
15377 bool Ignored;
15378 // If the value does not fit in the destination type, the behavior is
15379 // undefined, so we are not required to treat it as a constant
15380 // expression.
15381 if (FL->getValue().convertToInteger(IgnoredVal,
15382 llvm::APFloat::rmTowardZero,
15383 &Ignored) & APFloat::opInvalidOp)
15384 return ICEDiag(IK_NotICE, E->getBeginLoc());
15385 return NoDiag();
15386 }
15387 }
15388 switch (cast<CastExpr>(E)->getCastKind()) {
15389 case CK_LValueToRValue:
15390 case CK_AtomicToNonAtomic:
15391 case CK_NonAtomicToAtomic:
15392 case CK_NoOp:
15393 case CK_IntegralToBoolean:
15394 case CK_IntegralCast:
15395 return CheckICE(SubExpr, Ctx);
15396 default:
15397 return ICEDiag(IK_NotICE, E->getBeginLoc());
15398 }
15399 }
15400 case Expr::BinaryConditionalOperatorClass: {
15401 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E);
15402 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx);
15403 if (CommonResult.Kind == IK_NotICE) return CommonResult;
15404 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
15405 if (FalseResult.Kind == IK_NotICE) return FalseResult;
15406 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult;
15407 if (FalseResult.Kind == IK_ICEIfUnevaluated &&
15408 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag();
15409 return FalseResult;
15410 }
15411 case Expr::ConditionalOperatorClass: {
15412 const ConditionalOperator *Exp = cast<ConditionalOperator>(E);
15413 // If the condition (ignoring parens) is a __builtin_constant_p call,
15414 // then only the true side is actually considered in an integer constant
15415 // expression, and it is fully evaluated. This is an important GNU
15416 // extension. See GCC PR38377 for discussion.
15417 if (const CallExpr *CallCE
15418 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts()))
15419 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p)
15420 return CheckEvalInICE(E, Ctx);
15421 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx);
15422 if (CondResult.Kind == IK_NotICE)
15423 return CondResult;
15424
15425 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx);
15426 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx);
15427
15428 if (TrueResult.Kind == IK_NotICE)
15429 return TrueResult;
15430 if (FalseResult.Kind == IK_NotICE)
15431 return FalseResult;
15432 if (CondResult.Kind == IK_ICEIfUnevaluated)
15433 return CondResult;
15434 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE)
15435 return NoDiag();
15436 // Rare case where the diagnostics depend on which side is evaluated
15437 // Note that if we get here, CondResult is 0, and at least one of
15438 // TrueResult and FalseResult is non-zero.
15439 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0)
15440 return FalseResult;
15441 return TrueResult;
15442 }
15443 case Expr::CXXDefaultArgExprClass:
15444 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx);
15445 case Expr::CXXDefaultInitExprClass:
15446 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx);
15447 case Expr::ChooseExprClass: {
15448 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx);
15449 }
15450 case Expr::BuiltinBitCastExprClass: {
15451 if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E)))
15452 return ICEDiag(IK_NotICE, E->getBeginLoc());
15453 return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx);
15454 }
15455 }
15456
15457 llvm_unreachable("Invalid StmtClass!");
15458}
15459
15460/// Evaluate an expression as a C++11 integral constant expression.
15461static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
15462 const Expr *E,
15463 llvm::APSInt *Value,
15464 SourceLocation *Loc) {
15465 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
15466 if (Loc) *Loc = E->getExprLoc();
15467 return false;
15468 }
15469
15470 APValue Result;
15471 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc))
15472 return false;
15473
15474 if (!Result.isInt()) {
15475 if (Loc) *Loc = E->getExprLoc();
15476 return false;
15477 }
15478
15479 if (Value) *Value = Result.getInt();
15480 return true;
15481}
15482
15483bool Expr::isIntegerConstantExpr(const ASTContext &Ctx,
15484 SourceLocation *Loc) const {
15485 assert(!isValueDependent() &&
15486 "Expression evaluator can't be called on a dependent expression.");
15487
15488 if (Ctx.getLangOpts().CPlusPlus11)
15489 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc);
15490
15491 ICEDiag D = CheckICE(this, Ctx);
15492 if (D.Kind != IK_ICE) {
15493 if (Loc) *Loc = D.Loc;
15494 return false;
15495 }
15496 return true;
15497}
15498
15499Optional<llvm::APSInt> Expr::getIntegerConstantExpr(const ASTContext &Ctx,
15500 SourceLocation *Loc,
15501 bool isEvaluated) const {
15502 assert(!isValueDependent() &&
15503 "Expression evaluator can't be called on a dependent expression.");
15504
15505 APSInt Value;
15506
15507 if (Ctx.getLangOpts().CPlusPlus11) {
15508 if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc))
15509 return Value;
15510 return None;
15511 }
15512
15513 if (!isIntegerConstantExpr(Ctx, Loc))
15514 return None;
15515
15516 // The only possible side-effects here are due to UB discovered in the
15517 // evaluation (for instance, INT_MAX + 1). In such a case, we are still
15518 // required to treat the expression as an ICE, so we produce the folded
15519 // value.
15520 EvalResult ExprResult;
15521 Expr::EvalStatus Status;
15522 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects);
15523 Info.InConstantContext = true;
15524
15525 if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info))
15526 llvm_unreachable("ICE cannot be evaluated!");
15527
15528 return ExprResult.Val.getInt();
15529}
15530
15531bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const {
15532 assert(!isValueDependent() &&
15533 "Expression evaluator can't be called on a dependent expression.");
15534
15535 return CheckICE(this, Ctx).Kind == IK_ICE;
15536}
15537
15538bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
15539 SourceLocation *Loc) const {
15540 assert(!isValueDependent() &&
15541 "Expression evaluator can't be called on a dependent expression.");
15542
15543 // We support this checking in C++98 mode in order to diagnose compatibility
15544 // issues.
15545 assert(Ctx.getLangOpts().CPlusPlus);
15546
15547 // Build evaluation settings.
15548 Expr::EvalStatus Status;
15549 SmallVector<PartialDiagnosticAt, 8> Diags;
15550 Status.Diag = &Diags;
15551 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression);
15552
15553 APValue Scratch;
15554 bool IsConstExpr =
15555 ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) &&
15556 // FIXME: We don't produce a diagnostic for this, but the callers that
15557 // call us on arbitrary full-expressions should generally not care.
15558 Info.discardCleanups() && !Status.HasSideEffects;
15559
15560 if (!Diags.empty()) {
15561 IsConstExpr = false;
15562 if (Loc) *Loc = Diags[0].first;
15563 } else if (!IsConstExpr) {
15564 // FIXME: This shouldn't happen.
15565 if (Loc) *Loc = getExprLoc();
15566 }
15567
15568 return IsConstExpr;
15569}
15570
15571bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
15572 const FunctionDecl *Callee,
15573 ArrayRef<const Expr*> Args,
15574 const Expr *This) const {
15575 assert(!isValueDependent() &&
15576 "Expression evaluator can't be called on a dependent expression.");
15577
15578 Expr::EvalStatus Status;
15579 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
15580 Info.InConstantContext = true;
15581
15582 LValue ThisVal;
15583 const LValue *ThisPtr = nullptr;
15584 if (This) {
15585#ifndef NDEBUG
15586 auto *MD = dyn_cast<CXXMethodDecl>(Callee);
15587 assert(MD && "Don't provide `this` for non-methods.");
15588 assert(!MD->isStatic() && "Don't provide `this` for static methods.");
15589#endif
15590 if (!This->isValueDependent() &&
15591 EvaluateObjectArgument(Info, This, ThisVal) &&
15592 !Info.EvalStatus.HasSideEffects)
15593 ThisPtr = &ThisVal;
15594
15595 // Ignore any side-effects from a failed evaluation. This is safe because
15596 // they can't interfere with any other argument evaluation.
15597 Info.EvalStatus.HasSideEffects = false;
15598 }
15599
15600 CallRef Call = Info.CurrentCall->createCall(Callee);
15601 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
15602 I != E; ++I) {
15603 unsigned Idx = I - Args.begin();
15604 if (Idx >= Callee->getNumParams())
15605 break;
15606 const ParmVarDecl *PVD = Callee->getParamDecl(Idx);
15607 if ((*I)->isValueDependent() ||
15608 !EvaluateCallArg(PVD, *I, Call, Info) ||
15609 Info.EvalStatus.HasSideEffects) {
15610 // If evaluation fails, throw away the argument entirely.
15611 if (APValue *Slot = Info.getParamSlot(Call, PVD))
15612 *Slot = APValue();
15613 }
15614
15615 // Ignore any side-effects from a failed evaluation. This is safe because
15616 // they can't interfere with any other argument evaluation.
15617 Info.EvalStatus.HasSideEffects = false;
15618 }
15619
15620 // Parameter cleanups happen in the caller and are not part of this
15621 // evaluation.
15622 Info.discardCleanups();
15623 Info.EvalStatus.HasSideEffects = false;
15624
15625 // Build fake call to Callee.
15626 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, Call);
15627 // FIXME: Missing ExprWithCleanups in enable_if conditions?
15628 FullExpressionRAII Scope(Info);
15629 return Evaluate(Value, Info, this) && Scope.destroy() &&
15630 !Info.EvalStatus.HasSideEffects;
15631}
15632
15633bool Expr::isPotentialConstantExpr(const FunctionDecl *FD,
15634 SmallVectorImpl<
15635 PartialDiagnosticAt> &Diags) {
15636 // FIXME: It would be useful to check constexpr function templates, but at the
15637 // moment the constant expression evaluator cannot cope with the non-rigorous
15638 // ASTs which we build for dependent expressions.
15639 if (FD->isDependentContext())
15640 return true;
15641
15642 Expr::EvalStatus Status;
15643 Status.Diag = &Diags;
15644
15645 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression);
15646 Info.InConstantContext = true;
15647 Info.CheckingPotentialConstantExpression = true;
15648
15649 // The constexpr VM attempts to compile all methods to bytecode here.
15650 if (Info.EnableNewConstInterp) {
15651 Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD);
15652 return Diags.empty();
15653 }
15654
15655 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
15656 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr;
15657
15658 // Fabricate an arbitrary expression on the stack and pretend that it
15659 // is a temporary being used as the 'this' pointer.
15660 LValue This;
15661 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy);
15662 This.set({&VIE, Info.CurrentCall->Index});
15663
15664 ArrayRef<const Expr*> Args;
15665
15666 APValue Scratch;
15667 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
15668 // Evaluate the call as a constant initializer, to allow the construction
15669 // of objects of non-literal types.
15670 Info.setEvaluatingDecl(This.getLValueBase(), Scratch);
15671 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch);
15672 } else {
15673 SourceLocation Loc = FD->getLocation();
15674 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr,
15675 Args, CallRef(), FD->getBody(), Info, Scratch, nullptr);
15676 }
15677
15678 return Diags.empty();
15679}
15680
15681bool Expr::isPotentialConstantExprUnevaluated(Expr *E,
15682 const FunctionDecl *FD,
15683 SmallVectorImpl<
15684 PartialDiagnosticAt> &Diags) {
15685 assert(!E->isValueDependent() &&
15686 "Expression evaluator can't be called on a dependent expression.");
15687
15688 Expr::EvalStatus Status;
15689 Status.Diag = &Diags;
15690
15691 EvalInfo Info(FD->getASTContext(), Status,
15692 EvalInfo::EM_ConstantExpressionUnevaluated);
15693 Info.InConstantContext = true;
15694 Info.CheckingPotentialConstantExpression = true;
15695
15696 // Fabricate a call stack frame to give the arguments a plausible cover story.
15697 CallStackFrame Frame(Info, SourceLocation(), FD, /*This*/ nullptr, CallRef());
15698
15699 APValue ResultScratch;
15700 Evaluate(ResultScratch, Info, E);
15701 return Diags.empty();
15702}
15703
15704bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
15705 unsigned Type) const {
15706 if (!getType()->isPointerType())
15707 return false;
15708
15709 Expr::EvalStatus Status;
15710 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold);
15711 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result);
15712}
15713